KENWOOD TS-950SDX PAGE

Version 1: 31 March 06, Version 2: 6 May 06, Version 3: 18 Oct 2007, Version 4: 18 November 2007, Version 5: 21 Mar 2008

From a passionate Kenwood TS-950SDX owner. The 950SDX is proclaimed by many as one of the greatest transceivers ever produced.

This page is provided because:

·Some information here is not available anywhere else and should be useful to any TS-950 owner,

·Information does not exist in a single web site which is easy to follow,

·If the information remains available more TS-950s will be repaired and functional, (and probably improved),

The intention is to acknowledge the person who discover the information so questions can be sent to that person.

When information is already well documented and reliably maintained on another site then a hyperlink is made to that site to avoid yet another slightly different version.

I will publish all email feedback at the end of the page, so that whatever is discovered by others can be shared by all. Please email to jaking@es.co.nz

Yours sincerely

Jeff King ZL4AI / DU7

Disclaimer: No liability or responsibility whatsoever is taken for any of the information on this site. You assume total liability for any modification you undertake.
Copyright: Everything on this page

INDEX

FEATURES.. 2

OTHER IMPORTANT SOURCE OF INFORMATION: 6

KENWOOD RELEASED INFORMATION: 6

SERVICE MANUALS: 9

REPAIRS: 9

Raspy Audio Distortion.. 9

Raspy Audio sequel took a second repair: 22

The Return of Raspy Audio: Third Repair. 22

VCO 2 Problem.. 25

FINDING FAULTS BY INTELLIGENT ELIMINATION USING ANOTHER KENWOOD TRANSCEIVER.. 27

Battery Replacement.. 28

Jumping Frequencies all by Itself: Solution still Required.. 35

SHORTED FINALS: SYMPTOMS. 37

Preventing Final FETs failure. 38

Using multi meter to check if finals are ok?. 39

REPLACING FINALS. 40

LACK OF AUDIO: FAILURE OF CAPACITORS ON CONTROL BOARD.. 42

The terrible no volume 50 hertz audio hum. That drove me nuts. 43

INFORMATION NOT ANNOUNCED by KENWOOD: 46

1.8 Khz filter PROBLEM ???. 46

RM-1 Controller required for full control. 47

Service Menu Warning. 48

Part of DSP Circuit is missing. 49

MODIFICATIONS.. 50

[Kenwood] TS950SDX filters. 50

How I gave new ears to my TS-950sdx.. 51

TS-950SD general coverage transmit mod (1.8-30MHz Continuous TX) 57

Power On Funktions. 59

Allows sub-receiver to be on different band than Main receiver. 59

SERVICE MENU - 8.83 MHz I.F. TRANSMIT FILTER BANDWIDTH ENABLE MOD: 59

EXTENDED RECEIVER FREQUENCY RESPONSE MOD.. 63

Preventing final FETs failure. 64

Front-panel Sidetone Level Control for theKenwood TS-950S (may also apply to TS-950SDX) 64

ROOFING FILTER.. 65

PERFORMANCE. 65

KNOW PROBLEMS: 67

RFI Susceptibility.. 67

HELP WANTED.. 68

OTHER WEB SITES.. 68

Audio Modifications. 68

FEATURES

Swift performance and surgical precision are second nature to the TS-950SDX. Quality engineering blends aesthetic simplicity of form with a wide range of advanced features -- such as the built-in DSP (digital signal processor) and MOS FET final section. The result is exceptional transmission signal purity and first-class audio quality -- a benchmark for HF communications. And operating ease is just as impressive, thanks to the convenient menu system and many other user-friendly refinements.

Features at a glance:

	160 m ~ 10 m amateur band operation
	100 kHz ~ 30 MHz general coverage receiver
	Built-in DSP (Digital Signal Processing)
	Digital AF filters
	MOS-type FET final section
	Dual-frequency receive
	SSB IF slope tuning
	Menu system
	Automatic antenna tuner
	AIP system
	100 memory channels
	Built-in AC power supply

TS-950SDX in detail:

Digital signal processor (DSP)
The digital accuracy and reliability offered by the built-in DSP, for both TX and RX, translate into an unprecedented advantage in HF communications.

Outstanding performance
Carrier suppression is more than 50 dB, and unwanted-sideband suppression is also greater than 50 dB.
Digital AF filters
15 LPFs for SSB and CW modes (with cutoff frequencies ranging from 600 Hz to 6 kHz), and 3 BPFs for FSK use (with a central frequency of 2200 Hz) are menu-selectable.
Digital filtering eliminates key clicks
Superior FSK transmission circuit
The data control oscillator provides rapid switching for the cleanest FSK signal. The operator can choose 170, 200, 425 or 850 Hz FSK shift.
Selectable sound quality
To ensure high-quality sound, there are 4 low-cut filters plus a through position, and 4 high-cut filters.

Dedicated Power MOS FET (MRF 150MP) final section
The TS-950SDX was the first amateur radio transceiver to feature an FET final section. Excellent linearity results in greatly improved transmitter performance and enhanced reliability.

Dual-frequency receive capability
For maximum convenience when operating split frequencies, the TS-950SDX can simultaneously receive two frequencies, which can be within 1 MHz of each other.

Independent IF & AF circuits for main & sub receivers
M/S (main/sub) select for operating sub receiver with main tuning knob
TF-SET (transmit frequency set) and "delta" F function
Independent CW filter (500 Hz) and S meter for sub receiver
Simultaneous, independent monitoring
Using an external speaker or headphones, main and sub receivers can be monitored simultaneously yet independently; monaural and mixed monitoring are also available.

Powerful menu system
Rapid, user-friendly access to the many features and functions of the TS-950SDX is provided by the menu system. This includes 32 menus for power-on settings, and a further 29 menus for use during transceiver operation.

Quick Memory
The Quick Memory feature allows for stacking and recalling frequency, mode and filter information on the fly. The 5 channels reserved for this purpose are independent of main memory.

Automatic antenna tuner
Built into the TS-950SDX, for maximum operator convenience, is a completely automatic antenna tuner (compatible with impedances of between 20 and 150 ohms), controlled by a microprocessor preprogrammed to rapidly tune for minimum SWR.

First-rate receiver performance and sensitivity

Superb frequency stability
A TCXO (temperature-compensated crystal oscillator) and microprocessor-controlled digital PLL, DDS circuits control the frequency in 1 Hz steps. Consequently, the reference frequency (20 MHz) is accurate to within ±0.5 ppm between -10 degrees and +50 degrees C.
AIP system
AIP (Advanced Intercept Point) is an exclusive circuit design that provides superior dynamic range (when AIP is selected). The use of two selective RF amplifiers results in a significantly reduced noise floor level.
15 band-pass filters
The RF amplifier section and 15 band-pass filters -- including 10 BPFs for amateur bands -- together offer outstanding two-signal characteristics.
Selectable IF filters with memory

Innovative interference reduction

SSB IF slope tuning
For LSB and USB modes, independent high-cut and low-cut controls permit the operator to select the ideal IF passband width quickly and easily.
IF VBT & AF VBT
With the variable-bandwidth tuning control, passband width can be adjusted without affecting the centre frequency. In CW, FSK and AM modes, the IF VBT control allows the operator to avoid interfering signals while maintaining optimal signal-to-noise ratio.
High-precision IF notch filter
Available for all modes except FM, the tunable IF notch filter provides approximately 45 dB of attenuation in a very narrow frequency range.
Dual-mode noise blanker plus noise-select function
The blanker offers two modes -- NB-1 ("pulse") and NB-2 (longer duration noise) -- and can be tailored to match specific noise and signal level conditions. Also, by dedicating the sub receiver to noise detection and using its blanking pulse to blank the main receiver, the operator can soon determine the optimum setting.

High-performance CW functions

Full break-in and semi break-in
Reverse mode
In reverse mode the pitch of interference competing with the CW signal is reversed, so the operator can approach the target from either side.
Variable pitch control
Using the pitch control, CW pitch frequency can be varied between 400 Hz and 1000 Hz in 20 Hz steps. Current pitch frequency can be checked using the menu system.

100 memory channels
The TS-950SDX is equipped with channels 0-89 for independent storing of transmit and receive parameters such as frequency, mode, filter setting, auto-tuner and tone frequency. Memory channels 90-99 can be used to establish the upper and lower limits for the programmable band marker.

Versatile scanning
Any or all of the memory channels may be scanned, with selected channels skipped using the programmable memory channel lock-out function. The TS-950SDX can scan up to 10 groups automatically within the limits specified by the programmable band marker, and can also scan sub-receive frequencies. Scan speed can be varied continuously using the RIT/XIT control.

Other Features:

	10 direct band access keys
	Dual digital VFOs with A=B key
	Multi-function display and digital bar meter
	Ultra-fine (1 Hz) tuning with Direct Digital Synthesizer (DDS)
	4-step (0, 6, 12, or 18 dB) RF attenuator
	Switchable AGC circuit (OFF/AUTO/SLOW/MID/FAST)
	All-mode squelch circuit
	RM-1 remote function keypad (supplied)
	All-mode data communications
	Optional IF-232C interface for computer control
	All-mode RF output power control
	Built-in AC power supply

Dimensions (W x H x D)

402 x 141 x 400 mm (15.83 x 5.55 x 15.75 in.)

OTHER IMPORTANT SOURCE OF INFORMATION:

The TS-940 page

http://homepages.ihug.co.nz/~jaking/TS-940_02.htm

has the following which is equally relevant to the TS-950:

-Sources of parts,

-Links to useful sites, including manufactures, and containing Kenwood TS-950, TS-940 + TS-930 information

-Identifying when the radio manufactured [from serial number, establish date and unit number of productions that month]

KENWOOD RELEASED INFORMATION:

KENWOOD AMATEUR SERVICE BULLETINS

Available at: http://www.kenwood.net/indexKenwood.cfm?do=SupportFileCategory&FileCatID=1

ASB1016.JPG TS-950 Hum With Monitor On S/N 1060XXX 55.06 KB

ASB1017A.JPG TS-950 Noise When NB1 On For Sub Receiver 48.23 KB

ASB1017B.JPG TS-950 Noise When NB1 On For Sub Receiver 39.03 KB

ASB1018A.JPG TS-950 14.200 Mhz Transmit Spur S/N 1010XXX 63.92 KB

ASB1018B.JPG TS-950 14.200 Mhz Transmit Spur S/N 1010XXX 41.38 KB

ASB1019.JPG TS-950 Low Power Output After Temperature Protect 63.72 KB

ASB1020.JPG TS-950 Infinite SWR At Beginning Of Transmission 62.99 KB

ASB1021.JPG TS-950 Smoke From Antenna Tuner 54.63 KB

ASB0990A.JPG TS-950 Final Amp.Bias Circuit Change 84.81 KB

ASB0991.JPG TS-950 Rear Cooling Fan/Power Down 60.30 KB

ASB0959A.JPG TS-950SD Speech Processor Noise 83.41 KB

ASB0959B.JPG TS-950SD Speech Processor Noise 29.23 KB

ASB0959C.JPG TS-950SD Speech Processor Noise 49.95 KB

ASB0960.JPG TS-950SD Low VS-2 Audio 78.79 KB

ASB0961.JPG TS-950SD N.B. Gate Switching Noise 72.23 KB

ASB0962A.JPG TS-950SD RX-TX Switching Time With Amp 81.11 KB

ASB0962B.JPG TS-950SD RX-TX Switching Time With Amp 33.25 KB

ASB0963A.JPG TS-950SD RX Noise On 10 & 15 Meters 74.17 KB

ASB0963B.JPG TS-950SD RX Noise On 10 & 15 Meters 61.74 KB

ASB0964A.JPG TS-950SD Two Second TX Delay With Moni Switch On 75.60 KB

ASB0964B.JPG TS-950SD Two Second TX Delay With Moni Switch On 31.57 KB

ASB0971A.JPG TS-950SD Receiver Noise With Volume At Minimum 60.77 KB

ASB0971B.JPG TS-950SD Receiver Noise With Volume At Minimum 29.63 KB

ASB0982A.JPG TS-950SD TX Image On 18.115 MHz Causing Distortion 73.24 KB

ASB0982B.JPG TS-950SD TX Image On 18.115 MHz Causing Distortion 48.49 KB

ASB0984A.JPG TS-950SD 80 Meter Spurious Emmision On 80 Meters 73.46 KB

ASB0984B.JPG TS-950SD 80 Meter Spurious Emmision On 80 Meters 46.42 KB

ASB1024A.JPG TS-950SD Transmit Spurs 62.49 KB

ASB1024B.JPG TS-950SD Transmit Spurs 53.20 KB

ASB1052.JPG TS-950SD Spur on 18.115 MHz 72.75 KB

ASB0998A.JPG TS-950SDX Random Transmit When Mode Is Changed 64.61 KB

ASB0998B.JPG TS-950SDX Random Transmit When Mode Is Changed 34.13 KB

ASB0999A.JPG TS-950SDX No Beep In Headphone When Using Mono Phones 68.53 KB

ASB0999B.JPG TS-950SDX No Beep In Headphone When Using Mono Phones 44.45 KB

ASB1001A.JPG TS-950SDX Distorted DRU-2 Transmit Audio 61.62 KB

ASB1001B.JPG TS-950SDX Distorted DRU-2 Transmit Audio 34.31 KB

ASB1003A.JPG TS-950SDX K1EA Ver.8 Program Problems - New Eprom 76.80 KB

ASB1003B.JPG TS-950SDX K1EA Ver.8 Program Problems - New Eprom 54.25 KB

ASB1007.JPG TS-950SDX Speech Processor Adj/Excessive Noise 63.88 KB

ASB1009.JPG TS-950SDX 3rd Order Imd Improvements 53.36 KB

ASB1009A.JPG TS-950SDX 3rd Order Imd Improvements 62.17 KB

ASB1012.JPG TS-950SDX Key Click With Bug Type Key 50.74 KB

ASB1026A.JPG TS-950SDX Click Noise When Notch Is On 73.35 KB

ASB1026B.JPG TS-950SDX Click Noise When Notch Is On 54.08 KB

ASB1043.JPG TS-950SDX Installation Of YG-455S1 68.64 KB

ASB1045.JPG TS-950SDX No Vfo B After Split Operation/Micro Change 64.45 KB

ASB1047A.JPG TS-950SDX Carrier Point Adjustment 75.49 KB

ASB1047B.JPG TS-950SDX Carrier Point Adjustment 82.27 KB

ASB1047C.JPG TS-950SDX Carrier Point Adjustment 59.18 KB

ASB1050A.JPG TS-950SDX Sub Band Residual Noise 73.66 KB

ASB1050B.JPG TS-950SDX Sub Band Residual Noise 47.28 KB

ASB1053.JPG TS-950SDX Change Of Final Gate Resistor Type 76.53 KB

ASB0989A.JPG DRU-2 Erratic Playback/Memory Loss P.1 64.61 KB

ASB0989B.JPG DRU-2 Erratic Playback/Memory Loss P.2 34.65 KB

ZL4AI found some of the diagrams Kenwood put on the web cannot be read. Legible versions can be obtained by emailing Kenwood. It helps to point out there is considerable Health and Safety issue / liability fro Kenwood if an Amateur using information makes a mistake because the information Kenwood provided could not be correctly interpreted.

SERVICE MANUALS:

These can be found from time to time on the internet. If you need a service manual, we offer it on a comprehensive CD-ROM, which contains in PDF format:

- Service Bulletins (above)

-TS-950S and SD service manual,

-TS-950SDX service manual,

-TS-950SDX operators manual,

-TS-950SDX promotional brochure (in full colour),

-MC-90 operators manual

If you require the CD cost is $US10.00 plus postage. Please jaking@es.co.nz to request delivery.

REPAIRS:

This is the main reason for preparing this page. So useful repair information not easily available is in one place.

Raspy Audio Distortion

Symptoms experienced by ZL4AI

- When using an amp [SB201] started getting very distorted scratchy transmit audio.

- Turn 950sdx off. Leave say 20 minutes. Turn on and noise usually gone, for another 10 minutes of transmission.

-Did not use the 950sdx much for 3 months.

-With different amp [SB221] the same distorted transmit audio.

- Processor meter reading completed disappeared. Processor seems to work OK , but regardless of where you turn the control nothing shows on the meter. Cant seem to bring back the processor reading

If just use the radio alone then the transmit audio appears OK.

-Then after a couple of more weeks received audio becomes very distorted and lower level.

-Turn radio off for 10 minutes and received audio is OK.

- Distorted audio tends to occur first at top of band: E.g. Distorted at say 14315 but tune down to sat 14180 and no distortion. Leave 950 running and distortion audio moves down band to 14180.

ZL4AI suspected the faults could be one of:

- Kenwood published fix of reordering the connections to CP1, CP2, CP3 and CP4 on the PLL board, or

-Amateur service bulletin 1007: Reports of low: comp meter sensitivity, or noise on the transmitted audio when using the speech processor is normally a result of mis adjustment of the proc in control. The control is very sensitive and is difficult to adjust properly.

Further inspection showed that ASB 1007 had already been completed.

ZL4AI found the following advice on the Kenwood Archives:

----------------------------------------------------------------------------------------

[Kenwood] TS950SDX Distorted TX audio

John Tait bravo@iol.ie

Wed, 6 Nov 200200:36:46 -0000

Awhile ago, I post a request for help with a problem on a TS950SDX. It had intermittent distortion on the "Moni" audio,

and also occasionally on the TX audio. Unfortunately, nobody came up with a solution..

       Anyway, I sent it off to the "premier??" repair shop in the UK.. It was returned, unrepaired, with a note saying

  "this a common problem with 950s, there's no real cure for it"..    Eh??

    Class A1 certified nonsense..!!

I once more turned to the web for help... Lo and behold..... On searching www.mods.dk. for inspiration...There it

was..under "Countermeasures against cold solder joint at resistor block CP1-CP4 in PLL unit" the exact symptoms,

AND the cure thrown in for good measure..!

  We're now up and running perfectly again..

           THANK YOU  www.mods.dk.

John  EI7BA  http://www.iol.ie/~bravo/

----------------------------------------------------------------------------------------

[Kenwood] TS950SDX, distorted xmit and rcv

Draper, Bruce L draperbl@sandia.gov
Thu, 25 Sep 2003 13:09:12 -0600

Six months ago, my TS950SDX would have distorted signals, only on transmit, only with the internal tuner in line, and only

after being on the air for a half hour or so. Three months ago, it also started happening when NOT using the internal

tuner. Now the raspy signals are also on receive. Seems to be all bands, all modes, although I haven't done an exhaustive

search.

Is this a known problem with a straightforward fix? If not, where's the best repair center?

   Thanks,

      Bruce, AA5B

         BruceAA5B@aol.com

----------------------------------------------------------------------------------------

[Kenwood] TS950SDX, distorted xmit and rcv

John Tait bravo@iol.ie

Thu, 25 Sep 2003 21:25:26 +0100

Hi Bruce ..

       Go to  http://www.mods.dk/index.htm

Then to Kenwood..... 950... and look for the bulletin  "Countermeasure against cold solder joint at the resistor block;

CP1-CP4 in the PLL unit."

        I had the same problem, and this cured it..  BTW  I found that the best way to resolder the joints to CP1-CP4, was

to scrape the paint off the trace a fraction out from the pins, solder to the trace, and let the solder run back to the

pins. I created shorts between pins, when I tried to solder directly to them.. I also soldered some of the plated through

holes in the vicinity of CP1-CP4, and it was cured..  Use a good iron...NOT TOO HOT!

      Good luck OM

                      John EI7BA  http://www.iol.ie/~bravo/

Counter measure against cold solder joint at the resistor block; CP1-CP4 in the PLL unit.

Phenomenon:

Sub-band reception is deteriorate or receiving audio is intermittent distortion.

Transmission monitoring audio is distorted.

If you find the malfunction at stated above, take the following procedure.

Cause:

Cold solder joint of resistor block; CP1-CP4 in the PLL unit (X50-3170-00). In the manufacturing process, the temperature

in the reflow soldering furnace was lower than specified and the connection was insufficient.

Temporary: Add more solder to the resistor block; CP1-CP4 (at all pins) in measure the PLL unit (X50-3170-00).

Permanent: review the whole temperature control system of the reflow furnace to manufacture the Printed Circuit Board at more adequate temperature.

PC Board (Component side view).

From: "Jeff King" <jaking@es.co.nz

To: <clif@avvid.com

Sent: Wednesday, February 23, 2005 11:24 PM

Subject: CQ KA5IPF Questions about how to diagnose TS950sdx faults

Hi Cliff,

"Counter measure against cold solder joint at the resistor block; CP1-CP4 in the PLL unit..htm:"

This came from www.mods.DK. I have no idea if this is a known or reliable fix for the 950 because the origin is not shown. It sounds like

my problem, excepting the failure of comp meter. Have you seen this before Clif, or do you know anything about this repair?

I look forward to receiving your advice.

Yours sincerely

Jeff King ZL4AI

From: Clif Holland [mailto:clif@avvid.com]

Sent: Friday, 25 February 2005 12:39 p.m.

To: jaking@es.co.nz

Subject: Re: CQ KA5IPF Questions about how to diagnose TS950sdx x faults

That is a very common repair on the 950's. The SDX was supposed to have been fixed though. I would try it and see what happens, other than that [and previous advice on making sure there is good RF ground] I don't have any ideas.

Clif Holland, KA5IPF

www.avvid.com

ZL4AI emailed symptoms to

John Tait [johnei7ba@eircom.net]:

John advised:

Distorted TX audio could be to do with the CP1-CP4 thingy.. On mine, at the start, it ONLY happened with the ATU in circuit. In other words, when there was RF around the CP1-CP4 chips. With an Amp in circuit, the amount of stray RF around the shack is increased.

My processor meter was not affected and continued to function.

ZL4AI Question to EI7BA:

Has this “Countermeasure against cold solder joint at the resistor block; CP1-CP4 in the PLL unit" repair worked over the long term,

and is your 950sdx still working well?

I sold it to my neighbour EI8HT.... It has work flawlessly..I'm trying to buy it back..{:o)

ZL4AI emailed AA5B the above symptoms as well

AA5B replied:

Jeff -

The problems you describe in your eMail sound just like mine.

The repair guy who fixed mine said that it was a classic/common problem, and that re-soldering a few parts in the PLL fixed it up very nicely.

His name is Randy Starace, eMail randy@kk7tv.com

Web site: http://www.kk7tv.com

Good luck!

-Bruce AA5B

From: Jeff King [mailto:jaking@es.co.nz]

Sent: Friday, 25 February 2005 3:04 p.m.

To: 'randy@kk7tv.com'

Subject: Advice on how to fix TS950sdx faults.

Randy,

I have a TS-950SDX with faults described below. The internet has led me to believe that you may know how to fix the problem 3, as you have fixed problem 3 in the past. Please see the referral about your advice below.

THE FAULTS ARE:

0. Comp meter has stopped functioning.

1. Leave TS-950SDX on receive only for 7 hours no receive problems at all.

3. After 20 to 40 minutes (simultaneous listening and transmission)receiver (only tested on USB) goes distorted (raspy) and stays distorted [and unintelligible]. Like you are tuned way off frequency. The transmission audio also become distorted. If you turn radio off and on, the distortion clears for a couple of minutes, but then comes back. This distortion seems to start at the top of the band and progressively covers the whole band. It can be distorted at the top of the band but clear at the bottom.

2. If I use the SB221 amp then this seems to set off the distortion sooner. I have substantially rebuilt and improved the new ground which seems to have decreased the onset of distortion.

FOR YOUR INFORMATION:

attached is: "Countermeasure against cold solder joint at the resistor block;

CP1-CP4 in the PLL unit..htm:"

This came from www.mods.DK. I have no idea if this is a known or reliable fix for the 950 because the origin is not shown. It sounds like my problem, excepting the failure of comp meter.

I look forward to receiving your advice.

Yours sincerely

Jeff King ZL4AI

From: Randy Starace [mailto:randy@kk7tv.com]

Sent: Friday, 25 February 2005 3:12 p.m.

To: jaking@es.co.nz

Subject: Re: Advice on how to fix TS950sdx faults.

HI Jeff, yes that is the fix, do all the resistor packs on the DDS board and you will have it fixed

No need to solder the ICs 3 or 4.

Randy Starace

http://www.kk7tv.com

The Repair:

ZL4AI was nervous about soldering Surface mount technology and CMOS sensitive devices:

Solution was as follows:

- Obtain Hakko 936 ESD safe soldering station, with Hakko 907 ESD safe iron,

- Obtain Hakko tip 900-T-0.5C. As you can see this is very small and thin, and helps to prevent too much solder, and heat to be transmitted to the CP pins. In fact when soldering against the larger foil areas of the board I had to turn the temperature of the station well up to get the solder to melt. At least this way you are very safe and sure you will not damage the TS-950sdx boards

- Obtain a working desk with anti static mat [with a high resistive connection to earth to prevent any current flow through your work surface], and a floor mat earthed and an earthed wrist strap so you discharge your self before you touch any components.

- Obtain rework solder flux: I used Electrolube SMFL Rework solder flux. http://www.electrolube.com/docs061/bsurface.html This was really the major factor that made soldering the CP pins so easy.

- Soldering: For each pin first I carefully scrapped off the paint coating with sharp craft knife. I also scrapped each pin of the CPP unit with the knife to remove the oxide. Then I sprayed on the SMFL, put a slight amount of solder on the small iron tip. Applied the tip, and because of the flux it immediately flowed. Down the pc board trace and the pin on the CP. The small amount of solder on the small trip meant I had no occurrences of solder bridges. And that SMFL just enabled solder to flow immediately.

- After the first couple I found it was faster and best to scratch the up say 10 pins and traces at a time, spray the SMFL once, and progressively solder all 10.

- On each CP unit not all pins are connected, so only some require soldering. Those to be soldered are:

- CP1 1, 2, 3, 4, 5, 6, 7, 10,16.

- CP2 1, 4, 5, 6, 7, 8, 9, 14.

- CP2 1, 2, 3, 4, 5, 6, 7, 10,16.

- CP4 1, 4, 5, 6, 7, 8, 9, 14.

- There is no way I could re-solder CP4 connector 14 to CP3 connector 10 because the traces are underneath the CPs. So this connector was not re-soldered.

In the circuit diagram from the Service Manual below you can see how to identify these pins.

When I removed the PLL board found 14 holes where solder had not gone right through the board. Marked with arrows. If you blow up this picture you can actually see the empty holes. I soldered all up these up.

From: Traian Belinas [mailto:traian.belinas@deck.ro]
Sent: Tuesday, 7 March 2006 8:47 p.m.
To: jaking@es.co.nz
Subject: Re: TS_950SDX. request for expert advice

Jeff, The holes are plated (conductive).
When wave soldered, some of the plated holes will be unintentionally filled with solder.
The solder have not to pass through holes!
So, the empty holes are ok, no need for soldering them!!!
Just check for continuity from one side to the other of the PCB holes and will see it.

I believe Traian’s advice, but as I had the board out it was not a difficult to re-solder the holes to remove all doubt.

It is worth mentioning that before soldering I checked each circuit with an ohm meter. They were all connecting.

The Outcome;

Turned on the 950sdx and the problem the raspy audio was gone. Have run the radio for many hours now for two weeks and it seems to be permanently fixed. Wow thank you to all who gave me email advice. [This has saved me the risk and huge expense of sending the 950sdx 2,000 kms to Kenwood Australia.]

Raspy Audio sequel took a second repair:

Worked well for 5 weeks. THEN …… Blasted raspy audio again!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

Can you imagine my frustration when the fault returned?

The fault was not as severe as before, and it came and went, while using the 950.

If I turned off the radio for 2 min raspy audio cleared.

After a while I thought I wonder if it is that CP4 connector 14 to CP3 connector 10?

So with PLL board out again, I put an ohm meter on this connection. NO CIRCUIT! FROM CONNECTOR 14 TO CONNECTOR 10

Couldn’t believe it. The resistance actually measured at 13.59 Mega Ohms.

At last I was able to measure the lack of connection. [So the advice is try measuring for the broken circuit(, but the connection may measure connected as this circuit had previously).]

I did melt the solder on these joints and it was circuit gain.

Not being entirely convinced these were good solder joints, I soldered an insulated jumper wire in parallel between them, to be absolutely sure.

As these connector 10 and 14 are the worst to get at, I would repair this joint first.

The Return of Raspy Audio: Third Repair

Symptoms: Transceiver running for 1.5 hours,

Testing with signal general to deliver a S9 signal to antenna input, when operating with a region where audio was functioning

Tuning up band, heard in speaker audio as follows:

14330 and below OK no unusual sounds pure sine wave sound ti\one

14337: very slight cackle

14345: small cackles

14360: hear sine wave tone but mostly cackle

14370 mostly cackle

14380: just cackle noise

14395: cackle

14418 s9 signal gone

14443: s9 signal gone

14490 ok sine wave

14505 ok sine wave

14697 ok sine wave

Established that running radio for 7.5 hours with case open for malfunction does not occur, so probably heat related.

Wondered if problem could still be a faulty CP1 to CP4 connection.

Drew out a better working diagram, below (this time it is as you look at the board)

and set out with an ohm meter……………………. To re-measure connections again!

CP3-16 to R136 measured as open circuit. >>>>>>>> Same old problem.

Soldered a jumper wire from CP3-16 to nearby through board connector to R136.

Ran for 9 hours and audio now appears fixed again. Hope it does not appear again! These CP connectors are difficult to obtain a fully soldered joint.

VCO 2 Problem

Symptom
From: "Paul McInnish - K4BET" <k4bet@bellsouth.net
To: "Kenwood Reflector" <Kenwood@mailman.qth.net
Sent: Wednesday, April 03, 2002 6:17 AM
Subject: [Kenwood] TS-950SDX Problem

After being turned on for 30-45 minutes, the audio on my -950SDX starts to distort,

gradually deteriorates to complete un-intelligibility and finally
will get a CW beeping (I believe the CW that is sent is the letters "AL"),
display digits goes almost blank (except a row of dots) and nothing works
(will not xmit, receive, display on the SM-230 is a straight line etc.,
etc.).

Turn it off for 15-20 minutes, works fine and the deterioration starts
again. Sounds like a heat problem.... but would be interested to know if
anyone else has had the same problem and the resolution?!?!

Anyone got any thoughts?

John Tait suggested:

Now the possibility of a problem with VCO 2 rears it's head... This is a well known problem on the TS850s, where the VCO goes out of adjustment, or one of the DDS chips goes flakey. I have NOT seen this on a 950 (yet), but I can do the adjustment on an 850 blindfolded, as it's such a common problem.

The following from Clif tells how to check the 950 adjustment..

John Tait

SOLUTION:

"On the AF unit (bottom of radio, left front, with knobs to you) locate the
smaller enclosed VCO. Beside it is TP2. Using a insulated adjusting tool
turn the small trimmer cap in the VCO several times to remove oxidation. The
set it to 5v measured at TP2 using a voltmeter.

This is the enclosed area with only one hole in it. DO NOT TOUCH the one
with 4 holes.

Clif Holland, KA5IPF
AVVid
Authorized Kenwood and Icom Amateur Service
www.avvid.com
1-800-214-5779

Subject: [Kenwood] TS 950SD

I have lost the frequency display on my 950. Turning the dial will

cause the display to return for about one second then the cw coded

message "UL" is sent and the frequency display goes out again. I

assume that the "UL" means the frequency synthesizer is "unlocked".

Any ideas where to start my search?

Resetting the microprocessor does not help.

Thanks

Mike W7AJ

*Hi Mike..

Check out Jeff King's site at

http://homepages.ihug.co.nz/~jaking/TS-950sdx.htm

Jeff has done a great job of collecting all sorts of useful info for

SDX users.

Scroll down his page to "VCO2 Problems" This one seems the most likely

cause of your problem.

Vy 73

John EI7BA http://www.iol.ie/~bravo/*

-----Original Message-----
From: kenwood-bounces@mailman.qth.net [mailto:kenwood-bounces@mailman.qth.net] On Behalf Of w7aj@charter.net
Sent: Saturday, 6 May 2006 3:59 a.m.
To: kenwood@mailman.qth.net
Subject: Re: [Kenwood] TS 950SD

I'm pleased to say that with the help I received regarding my 950 problem, the reference to the VCO 2 probelm was also my problem. The test point 2 next to the VCO2 was reading about 0.680 volts. By turning the trimmer several times to remove any oxidation, the 950 came back to life. I set the voltage to 5.0 vdc and all appears to be okay again.

This is the only problem in about sixteen years of ownership. One exception to that however was three pot. connections in the auto tuner that had never been soldered at the factory.

Thanks for the help!

Mike W7AJ

John:

Thanks! That solved my problem.

73'

Mike W7AJ

-----Original Message-----
From: John Tait [mailto:bravo@iol.ie]
Sent: Friday, 5 May 2006 8:35 p.m.
To: Jeff King
Subject: K7AJ

*Hello Jeff..

See below .. Another scalp for your Totem Pole.. {:o)

Your site is saving me a lot of effort. I don't have to write long

emails anymore..

I just refer them to your site..

Vy 73

John EI7BadApples

FINDING FAULTS BY INTELLIGENT ELIMINATION USING ANOTHER KENWOOD TRANSCEIVER

The following is very clever way to use another Kenwood radio eliminate one section or other of the radio as functioning correctly.

From: Traian Belinas [mailto:traian.belinas@deck.ro]
Sent: Tuesday, 7 March 2006 8:47 p.m.
To: jaking@es.co.nz
Subject: Re: TS_950SDX. request for expert advice

You may use also an "intelligent" way of detecting the problem stage, an idea that just appeared to me.
It may be the PLL, the mic preamp, the balanced modulator, tx IF stage, etc.
You have the TS940 at hand, is it?
The both 950 and 940 are using the same IFs?! I think they do.
So, you may couple and listen the 455kHz Tx IF signal from the 950 to the 940 455 kHz Rx IF!
The same for the 8,83MHz IF.
A problem will be the signal levels, as the Tx chain levels from the 950 shall be too high for the Rx chain of the 940, so a ressistor shall be used for atenuating it.
Or may just coupling them as the 950 Tx IF to induce Rx signal on the 940 (capacitive coupling, may not need direct conection).
Another problem shall be avoiding radiating HF RF, so always use a dummy load for the 950 and disconnect the 940 IF from its RF unit.
I don't remember exactly, but small coaxial cables/connectors are used for the IF signal connections, so it may be easier than it looks...

Battery Replacement

Berry W6EZ serazin@pacbell.net
Sun, 28 Dec 2003 08:05:16 -0800

I just bought a TS-950SDX and I wondered what shape the memory back up battery

might be in.

After reading all the horror stories about battery leakage ruining the traces on the boards they are mounted

on in the 850s, I thought it would be a good idea to check the 950 for the possibility of the same problem.

As it turned out, my fears were well founded. Once I removed the top and bottom covers of the radio,

tilted the front panel forward I immediately noticed the tell tale signs of battery leakage, namely a

discoloration of the plating on the battery case.

Fortunately, I bought two of the batteries from Kenwood (it never hurts to have a backup)

so I had the parts and did the job while I had everything apart. The battery in my TS950SDX was the

same as in my 850.

I have uploaded a set of photos to

http://groups.yahoo.com/group/KenwoodTS-950SDX/

in the photos area and each photo has a caption that will help explain

what you are looking at in each picture.

This is not a hard job to do, from start to finish it was less than an hour, but I do have

a desoldering tool and that helps a lot.

====================================================

the part number from Pacific Coast Parts is: KW09-0514-05 it costs about $9.00

Another possible source of replacement memory batteries for the TS-
950SDX is Mouser Electronics. I just received a battery I ordered
from Mouser (along with a bunch of other parts), and it is identical
to the replacement battery I ordered a week ago from East Coast
Transistor Parts, Inc. The only difference was the price. East
Coast charged $9.71 for the battery. The price at Mouser was $2.30.
Both batteries are Sanyo CR2430 lithium batteries and the both have
identical PC board leads spot welded to them. For those who may be
interested, the Mouser part number is 639-CR2430-FT1. (Note: Mfg
P.N. CR2430-FT1). Mouser's web site is http://www.mouser.com.
Phone: 1-800-346-6873.

Frank (KKØK)

Jumping Frequencies all by Itself: Solution still Required

-----Original Message-----

From: Michael Ditmore [mailto:michael@rangefire.com]

Sent: Sunday, 23 July 2006 7:42 a.m.

To: International Radio

Cc: jaking@es.co.nz

Subject: Re: 950SDX

Dear Jeff and George

This is the most (and fastest) feedback I have ever had on a 950!

Thanks...

I am about to do the battery replacement + MARS freq mods and will also put on a new front panel at the same time ($77 from Kenwood parts)... if I'm feeling gutsy after that I'm planning to tackle some of the crazy guy's mods (WZ5Q) which look interesting – especially the audio line input.

Right now I am running a Symetrix 528e right into the normal mic input and getting great reports (think how much better it could be :-)

As I said, I am plagued on 75 (only) by these intermittent jumps in IMD and can only imagine leaky diodes (temp driven) as the cause.

From time to time the rig will jump down to a freq of 1.71xxx on its own and I suspect this is the low battery or some faulty inter-board connection.

Again, best of thanks and please put me on your 950 distribution.

Michael

W7HUT

On Jul 23, 2006, at 12:18 AM, Jeff King wrote:

Michael,

If you prepare am email with a full description of your 950s IMD symptoms, I am more than happy to post it on the 950 page. Someone maybe more than happy to provide a solution.

Freezing suspect capacitors sounds an good idea.

Yours sincerely

Jeff King

-----Original Message-----
From: Michael Ditmore [mailto:michael@rangefire.com]
Sent: Tuesday, 17 October 2006 5:01 p.m.
To: jaking@es.co.nz
Subject: Re: 950SDX

Jeff:

This is an update to the message below -

I successfully performed the battery replacement and MARS mods this weekend and the 950SDX seemed to be back to its old self... no more IMD problems.

However 24 hours later one original problem has reappeared.

I will be receiving on 75 and without warning the VFO (in this case

A) will beep once and switch to 1.8 MHz

Memory functions are fine and I can return immediately to the original frequency, sometimes for seconds, sometimes for hours, until it happens again.

New battery, no other symptoms.

Anyone else seen this?

Michael

W7HUT

SHORTED FINALS: SYMPTOMS

----- Original Message -----

From: "Bob Arenella" <rja12@comcast.net

To: <kenwood@mailman.qth.net

Sent: Sunday, September 30, 2007 10:03 PM

Subject: [Kenwood] Sick TS-950S

Hello all,

New to the list. I recently picked up a TS-950S that has a problem. I found the 7.5 amp fuse in the power supply was blown. Replace it, powered up & the display came on for a fraction of a second & fuse blew again. I don't know the history of this rig, as the seller was not a ham. He knew it had a problem & sold it for a price so low I couldn't pass it up.

Regards,

Rob

N2OAM

Most likely, shorted finals.

Clif Holland KA5IPF

www.avvid.com

Preventing Final FETs failure

Contact author. Contact author:

Tony, I0JX

My suggestion is to replace the two 22-ohm 0.5-W resistors marked R15 and R16 with carbon-type resistors of same value but higher power (e.g. 1 W).

Those resistors are located in the "Final Unit", not too far away from the final Field Effect Transistors (FETs). Replacing them is fairly easy. The rationale for the proposed modification follows.

I have my TS-950SDX since about 13 years. In year 2004, the final FET marked Q4 2/2 unexpectedly failed, with no apparent reason. A circuit check showed no problem whatsoever, therefore I attributed the failure to an occasional fault, and I then just replaced the faulty FET with a new one. But in year 2005 it failed again. Then, before replacing the FET another time, I performed a very accurate circuit check.

With the aid of a magnifying lens, I realized that resistor R16 had got a bit deformed at its center, taking a "barrel" shape. After carefully inspecting and testing that resistor, it was evident that it had overheated and that it was subjected to an intermittent contact.

At times when that R16 opens up, the RF drive voltage on FET Q4 2/2 gate grows up a lot, causing its failure. Evidently that resistor is undersized, as it does not withstand the applied RF drive power.

=====================================================================================================

ZL4AI found R15 and R16 measured 22.4 ohms and 22.7 ohms. (Maybe they are deteriorating? Unknown if theses are 5% tolerance resistors. If they are 5% tolerance upper value is 23.1 ohms )

Replaced with from RS Components

477-1510 RES METAL OXFILM 1W 22 OHM 5% Matsushita Electric Industrial. These measured 21.9 to 22.0 ohms.

After replacement I thought it was important to adjust the final unit voltage and current for new components

Service manual page 199 item 9 defines how to set up

Final Vcc

Drive Icc

Final Id

Note that Drive Icc and Final Idd are set in USB mode.

NOTE THIS WELL BECAUSE I TRIED TO SET Final Idd in CW mode, and it overshot to give reading on 150 mV approx,

There was flash, and Q4 ½ and Q18 were destroyed.

Not a happy repairer who had been undertaking preventative maintenance.

In hind sight I would have been better to wait until finals failed before replacing them.

Caution just progressively turn these potentiometers up to required voltage setting. Do not turn potentiometers higher than the specified limits. The safest way is to not transmit. Turn the put up a milli fraction of a turn. Transmit and quickly stop transmitting if you have turned too far. Slowly does it there is no reason to rush like I did and make a $250 mistake.

Using multi meter to check if finals are ok?

Disconnect the or take the following components off the final board by unsoldering:

Off the board

Q18, Q19

Unsolder 1 lead

C48, C49 C50, C51

C42, C43, C44, C45, C46, C47

R15, R16, R17, R18

This lead the gates of the MRF150s open.

Use to multi-meters to test.

Connect 1 between reading resistance between the drains and ground. Ie. Across the drain to source.

For the good transistor This read about 5.6K once the meter stabilised.

Use the other meter set in diode test mode to apply voltage between the gate and source. Use no more than 2.6 volts. Check this voltage with the other meter before you apply it.

If the transistor is working it will turn on, and the drain to source resistance will drop to 13 ohms.

Then reverse the 2.6 volts on the gate to source and this will turn the MRF150 off and it will read 5.6K again.

In the MRF150 I had destroyed:

- gate to source measured resistance about 23.3 Mega ohms.

- On good MRF150s gate to source resistance or gate to drain resistance showed no connection whatsoever.

On good MRF150s drain to source varied a lot, between, 5.5 kilo ohms, 16.25 kilo ohms, 0.12 mega ohms, 0.62 Mega ohms

Data Sheets for MRF150s are here:

The original is Motorola

http://www.ortodoxism.ro/datasheets/motorola/MRF150.pdf

The semi conductor division of Motorola was sold to M/ACom.

http://www.ortodoxism.ro/datasheets/macom/MRF150.pdf

So in effect M/Acom are identical, and seem to be cheaper to buy.

REPLACING FINALS

The MRF150s are Mosfets and are very easily damaged by static electricity. Especially the gate connector is very sensitive. So there are special steps to soldering them in. beware you could destroy them by touching them.

1. Work with wrist strap grounding you to your radio ground wire,

2. Ground your soldering iron tip, bay wrapping wire round the barrel and attaching that to your radio ground wire,

3. work on a grounded surface. I found the idea was the 950sdx heat sink where the finals came out of. I just attached that to the radio ground wire.

That way all 3 items were at zero volts, and there was lots of metal in the radio body for my hand to touch to be sure they remained free of static charges.

Now take the new MRF150 transistors and tin the gold connectors. Easiest way is to use one screw and attach them to the grounded heat sink as soon as they come out of the antistatic wrapping.

After that get a very thin copper wire and solder it in a ring (on the top side) around the 4 connector tabs. Now you have the transistor in a safer handling state

Bolt the finals board to the heat sink. Screw the new MRF150s in place. Then progressively solder on each gold tab to the board.

After that slowly unsolder the ring wire and remove it.

Take careful note of where the two insulating Mica Washers / spacers insulate Q1 and Q8 from the heatsink. Neither of these transistors is grounded, and the Q1 also has plastic washers insulating the attachment screw from the body. This point is not well explained or illustrated, in the service manual

Not recommended practice / This is the wrong way to set up finals

After I blew up Q4 1/2 and Q18:

I found that VR4 on my radio made no difference where it was turned. ???

Turning VR5 was effective set TP2 voltage up to 90 to 110 millivolts.

So I was puzzled as to how to set VR4 correctly so as to not put excessive current into the transistors.

The schematic on page 227 shows transmit voltage at the emitter of Q18 to be 2.3 volts.

VR4 adjusts the base of Q18.

On transmit I used a digital volt meter and turned VR4 to set the emitter of Q18 to be 2.3 volts.

Then I turned VR5 to set up TP2 to read 104 millivolts after 1 min of transmit. TP2 reads about 90 millivolts after 10 seconds of transmit and slowly climbs to 104 millivolts over the next 50 seconds.

VR5 adjusts the base on Q5.

Then I measured the emitter of Q5 at 3.1 volts. The schematic on page 227 shows transmit voltage at the emitter of Q19 to be 2.6 volts. [So this is reading 0.5 volts higher than spec]

There is specified differential of 0.3 volts 2.3v compared with 2.6v between the emitters of Q18 and Q19.

Possibly it might be better to achieved a more balanced condition than 2.3 and 3.1.

This could be done by adjusting VR4 to give slightly higher voltage say 2.5 volts at the emitter of Q18. Then reset VR5 to give 90 to 110 millivolts at TP2.

=====================================

When I used the radio setup like this I found I got:

180 watts output on 40 meters,

120 watts on 20 meters

And 80 watts on 10 meters

In fact I believe I was getting this output out of just 1 transistor.

The MRF150 outputs 300 watts so this is possible.

VR5 should only be set up to give 50mV at TP2.

LACK OF AUDIO: FAILURE OF CAPACITORS ON CONTROL BOARD

Hallo Jeff de Gabriele I4JXE,

I'm trying to fix a fault in my Kenwood TS-950SD s.n. 30600007, and a true Good source was yor internet site. TNX

The audio signal out of the speaker became barely perceptible even with the control full turned. The same coming by the sub-receiver. With the knob from middle to back no audio out a all. As with headphones into EXT SPK jack (the same happens at the speaker leads, with speaker removed) I hear a correct audio signal, I guessed that the AF PA (ic7 in the control borad) was burned out, so I replaced it (a common operational amplifier TDA 2002), but

no luck, and still no audio. I have a complete set of repairing instruments, any suggestion to try to fix it by myself? (no help from the Kenwood service bullettins)

TIA es '73

Gabriele

From: jaking@ihug.co.nz

To: gbergami@hotmail.com

Subject: Re: Requesting help on TS-950SD

Date: Tue, 12 Jun 2007 15:59:33 +1200

Quick Suggestion:

Get Service manual

Find signal level diagrams for transmit signal.

In middle of manual. on one page only

THis requires injecting signal generator signal in antenna and measuring tracing the signal through the entire path.

Use this to identify where the signal decreases. then you should be bale to work though and identify which components

have failed.

Good luck

sounds like you will achieve repair.

Be interested to hear how you get on

Yours sincerely

Jeff King

From: gabriele i4jxe [mailto:gbergami@hotmail.com]

Sent: Wednesday, 13 June 2007 3:17 p.m.

To: jaking@ihug.co.nz

Subject: RE: Requesting help on TS-950SD

Rig repaired !

As I told you there was only an almost complete lack of audio output in my TS950SD, that anyway continued to work fine.

I usually work digital modes, with computer interface delivering the fixed audio out from the connector on the rear, so it wasn’t really

a big problem to me, but decided to bring back the rig to complete good health status.

I localized the fault in the control unit board (X53-3230-00), where the audio output from pin 4 of the amplifier IC7 (that is a TDA 2002)

Couldn’t go to the speaker across the polarized capacitor C7, a 220 microF./10v., that was open.

I changed it with a 220 microF./25v. one that look me more correct for the duty, and the job was done.

Doing the job, I suggest to change even the two other capacitors near C7, C3 (1000 mF./16v) and C6 (470 mF./6,3v),

raising the working voltage to 25v.-

The AF amplifier microPC2002v IC7, that is a TDA 2002, should be changed with a TDA 2003, delivering a little more output power.

Again congrats for the good work for the Kenwood 940/950 family owners I will be glad to contribute to in the future.

Best regards

'73 de Gabriele, I4JXE

The terrible no volume 50 hertz audio hum. That drove me nuts

Fixed in Jan 2008

When ZL4AI turned the volume right down, there was this really irritating low level hum sounded like a power supply 50 hertz.

Tuned volume up and the hum disappeared into audio noise.

As I listen with headphones this really irritated me.

[How did I notice this? I have a 940 and 950sdx in A / B positions. Often I use the 940. the 940 has a very good receiver and really only the DSP quietness of the 950SDX appears to be better. At no volume the 940 was no noise at all…. But the 950SDX had this infuriating hum!]

I always wondered if this hum was not present, I would hear signals at low volume more clearly. I certainly could turn the 940 down into almost no volume with a very noisy band and often copy really improved. The almost no volume improvement was not possible with the 950SDX.

[If you have experienced turning volume right down and improving your copy, then you will understand what I mean].

For sure there was distinct possibility that the radio would be distinctly improved at DX low signal level copy.

[After fixing this, I can tell you the radio is considerably improved as a receiver. I now can 940 low audio level calrrity. The improvemet was worth very minute of the effort to find the problem]

For sure a $4,000 radio should not have this HUM.

But… how to find it / fix it ???????????????

What follows is probably really useful as a methodology.

I worked back wards up audio chain to eliminate all possible sources of sound, block unit by block unit.

Disconnected main audio feeds into each block to find the feed the sound came form.

A: Look at functional block diagram page 15 of Manual which shows the general sequence of audio signals.

B: Then look at Main schematic diagram p296, to see each of the connector numbers.

You will have work your way backwards and forward between A and B to figure out where each (audio or RF) signal comes from / to.

Then from the Main schematic diagram follow through these descriptions on the individual circuit board drawings for the Control Board, AF Board Switch board etc.

Note that SINGLE each wire is disconnected by taking off the connector and carefully removing the SINGLE wire OUT from the connector, and then reconnecting the other wires at the connector. This enables elimination of the problem SINGLE wire by SINGLE wire, signal by signal, and ground shield wire by ground shield wire. This single signal by signal elimination was the key to finding the fault.

BE CAREFUL NO TO REMOVE control wires that could result in damage to a board component. Only remove a wire when you have verified it is an incoming RF or audio signal.

The following sequence is Working progressively up stream.

Control Unit

Connector 9 disconnected: hum still there. Sub-receiver is not source

Connector 8 disconnected: hum GONE. Main receiver is source, and this comes form the AF board.

AF Board:

Tried disconnecting main inputs to this board.

Sequence below is important

Disconnect W1: main receiver input from signal unit: Hum still there: This is not source

Disconnect Connector 14-2 output from AF volume control: hums increases in level

Disconnect Connector 13-2 input from AF volume control: hums is gone

Reconnect Connector 14-2 and hum returns

Summary:

Disconnect both 14-2 and 13-2 and hum disappears

Connected both 14-2 and 13-2 and hum is quite low level

Disconnect either 14-2 and 13-2 and hum is louder

Connector 13-4 produces most hum and level increases as monitor circuit volume is turned up

Wondered if fault was fixed by Service Bulletin ASB 1050?

Installed 0.01 uF disc ceramic capacitor on switch X41-3520-B/10 as described in Service Bulletin ASB 1050.

All hum related to disconnecting AF Connector 14-3 disappeared completely….. Partial Success!

Following ASB 1050, and

Removed Control Board. And

….. all of C33, C34, C39 had already been installed as tantalium capacitors.

Observe that this radio already had ASB 1050 partially undertaken.

Note that it is worth verifying the modifications have been made because in this case only part of the modification was installed.

Now try Eliminating further other input signals to the AF Board

Disconnected connector 3-6 which is to IF board 15-SAF: hum is still present.

Found at Connector 12 wire 5 which is ground shield for wire 4- to SWA J/10-108-MONVRI was incorrectly connected to pin 3. and hence was not grounded at all. Shifted this ground wire back to pip 5.

Note my 950sdx is very original and mint condition. I am the third owner. As best I can tell I am the only person who has ever worked on this radio.

First owner was a short wave listener. Second won a collector who did not sue his radios much.

It is likely this ground wire in wrong place was factory error.

Changing the ground made no difference and the hum is still present.

Disconnected Connector 12-4: Hum still there, so hum no induced by monitor circuit.

Removed DRU2 units and hum still present, so not introduced by DRU2 circuits.

So traced from Connector 13-4 which is to SW A –E10 Connector 18-7 MONVR2:

Disconnected SW A –E10 Connector 18-7 and HUM IS GONE!

So source of Hum is SWA E/10

SWA E/10

Disconnected Connector 20-6 MONVR1: hum is still present.

Concluded hum must be coming ground leads to switch or in the switch itself.

As monitor volume is turned down MONVR2 has 10K ohms between its signal and earth, and the hums disappears.

This means the hum must becoming up the MONVR2 ground wire Connector 18-6 or Connector 20-5

Disconnected Connector 20-5 and THE HUM IS GONE!

Other end of Connector 20-5 is SW A J/10 Connector 109-2-GND

SW A J/10

Disconnected Connector 109-2-GND and hum is also gone.

FOUND THE HUM. It is in this ground wire Connector SW A E/10 Connector 20-5 to SW A J/10 Connector 109-2-GND

So how to leave this ground wire connected with no hum?

ARRL hand book 2004 recommends 0.01 uF disc ceramic capacitor to remove low frequency hums.

Permanent solution.

Permanently removed 109-2-GND form SW A J/10 Connector 109.

Soldered a 0.01uF disc ceramic capacitor to wire and another pi connector and pushed this into Connector 109-2-GND. The otther capacitor wire went to the removed 109-2-GND metal female socket. This was covered with insulation tape.

This is one modification you will never regret.

Also note. Only tools required were an ohm meter, a service manual, a soldering iron and small pliers.

INFORMATION NOT ANNOUNCED by KENWOOD:

1.8 Khz filter PROBLEM ???

-----Original Message-----

Subject: [Kenwood] 950SDX PROBLEM ???

Hi All,

         I may have a problem with my 950SDX---late model Mfd. in 1998. When I'm listening to

upper sideband, and select the 1.8 khz. filter, in order to have the audio sound good, I must take

the "high cut" slope tune knob and turn it 2 or 3 clicks counter-clockwise. If I do not, it sounds tinny.

It does not do this when listening on lower ideband, only on upper.

Those of you with 950SDX's and the 1.8 filter installed, please try this--let me know if yours does

this also. If you do not have a 950SDX and might know what the problem is, please let me know too.

940 & 850 users---please try it and let me know your results.

                                         Thanks,

RON

  ***********************************************************

                     RON GOLDSTEIN--KA2IIA

                      PUTNAM VALLEY, N.Y.

Dave Jaksa dave.jaksa@verizon.net
Mon, 2 Sep 2002 14:46:25 -0500

Ron,

That's the way mine has always worked and I have seen the same thing on two

other TS-950's that I have used.  I think it is a simple matter of having

the narrow 8.83 MHz SSB filter in there.

I also notice some of the same thing on LSB but to a much lesser extent.

Since I'm usually interested in a tighter bandpass when I use the 1.8 KHz

filter, I usually run the High Cut between the 3 and 4 o'clock position when

I switch it in.

73,

Dave, W0VX

--------------------------------------------------------------------------------

John hydro@naturecoast.net

Mon, 2 Sep 2002 16:13:55 -0400

The 950sdx carrier point ( receive only on the 950) is align for the 2.7khz filters. Anytime you go to other filter widths you have to recalibrate the

slope tuning to match the filter... This is normal with all radio , whether it has slope tuning or IF shift.. Unless the filters are DSP based like the 756 Pro or TS-870

73 john

RM-1 Controller required for full control

Bud Hippisley, K2KIR k2kir@telenet.net

Sun, 09 Mar 2003 23:38:06 -0500

There is no front-panel way to run CW or voice messages on the TS-950SDX. There _is_ such ability on the TS-850 -- at least for CW; I can't vouch for voice.

Rus Healy's review of the TS-950SDX in QST a decade or so ago specifically noted that the 950SDX was the first instance he knew of where the remote control provided (message) functionality not available on the front panel of the HF transceiver.

And yes, although the manual is not real clear on this point, you always get the CW message capability with a stock 950SDX -- but you must add the DRU-2 option to get voice message capability.

There is nothing magical about an RM-1. It's basically a few switches and a bunch of precision resistors. The switches switch different resistor values onto the hot lead of the shielded audio cable going from the RM-1 back to the jack on the rear of the transceiver. A simple A/D conversion circuit inside the 950SDX changes those different DC voltages into a variety of logical commands (one at a time, of course -- you can have only one DC voltage on the cable at a time). You can build up an RM-1 out of your junkbox parts or after a quick visit to Radio Shack.

Bud, K2KIR

Service Menu Warning

-----Original Message-----

Sent: Friday, March 03, 2006 7:13 AM

To: Kenwood@mailman.qth.net

Subject: Re: [Kenwood] kenwood TS-950SDX

james rich wrote:

Can someone tell me how to turn up the output power of this radio, I'm not sure what VR to turn,,,Thanks,,James //

N4CTR

My observation If you come into the service menu(3+9 and power switch on), the power is dropped to 100 watts, Even if to not touch an position 9 (100/150w), before an exit it is necessary to choose from the service menu In an position 9 - 150, and then to switch off or clr key

73! Ilya , RA4CTR

From: kenwood-bounces@mailman.qth.net on behalf of Hsu, Aaron (NBC Universal) [aaron.hsu@nbcuni.com]

Sent: Saturday, 4 March 2006 8:19 a.m.

Word of warning...