TS-940 Questions
- Kenwood Serial Number Lookup
- Kenwood Ts 850 Serial Numbers
- Kenwood Ts 950sdx Serial Numbers
- Kenwood Ts 530s Production Dates
- Ts 950sdx Serial Number Data
Kenwood TS-940S (TS 940 S TS940S). This change is applicable to units prior to serial number 606xxxx. Time required for this modification is 1 hour or less. I believe the TS940s were produced from 1985 until 1992. Kenwood serial number XYYZZZZZ X = last digit of the year YY = Production Month ZZZZZ = sequence in production for that month. View and Download Kenwood TS-940S instruction manual online. Kenwood TS-940S Transceivers: User Guide. TS-940S transceiver pdf manual download. TS-940S's in the serial number range of 601XXXX through 708XXXX may be limited n SSB peak power as compared to full CW output. The level may be increased by changing the value of capacitors C182 and C183 in the ALC circuit on the Control board. The recommended replacement value for each capacitor is 0.0022 uF, 50v (CK45B1H222K).
#276 I have a high serial number (12 mil) TS-940 that I just acquired and I have two questions ..... 1. The tuning rate is 3 KHz per revolution, not the 10 KHz that the manual states, and it doesn't change no matter how fast I spin the dial.... 2. Only every other band switch push button works....3.5 MHz, 10 MHz, 18 MHz, 24.5 MHz, and 29.0 MHz. I have reset the microprocessor, but no change.... Any ideas? Thanks, and 73.... Roger, WB9BXT. |
#277 The fix for strange problems like these seems to be cured sometimes by dropping the front panel (it hinges on a couple of screws), reseating the various connectors, and raising it again. You might try that before bringing out the scope and soldering iton. toggle quoted messageShow quoted textBob K6DDX On Friday, April 17, 2020, 11:19:31 AM PDT, Roger Hoffman <sooline@...> wrote: I have a high serial number (12 mil) TS-940 that I just acquired and I have two questions ..... 1. The tuning rate is 3 KHz per revolution, not the 10 KHz that the manual states, and it doesn't change no matter how fast I spin the dial.... 2. Only every other band switch push button works....3.5 MHz, 10 MHz, 18 MHz, 24.5 MHz, and 29.0 MHz. I have reset the microprocessor, but no change.... Any ideas? Thanks, and 73.... Roger, WB9BXT. |
#278 Bob: toggle quoted messageShow quoted textThanks for the tip....I'll give that a try as soon as I 'unwire' the radio from my operating desk. Roger, WB9BXT On Friday, April 17, 2020, 02:47:04 PM EDT, Bob Albert via groups.io <bob91343=yahoo.com@groups.io> wrote: The fix for strange problems like these seems to be cured sometimes by dropping the front panel (it hinges on a couple of screws), reseating the various connectors, and raising it again. You might try that before bringing out the scope and soldering iton. Bob K6DDX On Friday, April 17, 2020, 11:19:31 AM PDT, Roger Hoffman <sooline@...> wrote: I have a high serial number (12 mil) TS-940 that I just acquired and I have two questions ..... 1. The tuning rate is 3 KHz per revolution, not the 10 KHz that the manual states, and it doesn't change no matter how fast I spin the dial.... 2. Only every other band switch push button works....3.5 MHz, 10 MHz, 18 MHz, 24.5 MHz, and 29.0 MHz. I have reset the microprocessor, but no change.... Any ideas? Thanks, and 73.... Roger, WB9BXT. |
#279 Roger you don't have to unwire the radio. Just slide it forward on the desk then prop it up with a wood block high enough to allow the panel to swing down. This, after you remove the covers. Don't forget the middle screw on the bottom cover; it allows the cover to augment the heat sink for a voltage regulator. toggle quoted messageShow quoted textIf your cables are short you will indeed have to disconnect them. Bob On Friday, April 17, 2020, 04:14:07 PM PDT, Roger Hoffman <sooline@...> wrote: Bob: Thanks for the tip....I'll give that a try as soon as I 'unwire' the radio from my operating desk. Roger, WB9BXT On Friday, April 17, 2020, 02:47:04 PM EDT, Bob Albert via groups.io <bob91343=yahoo.com@groups.io> wrote: The fix for strange problems like these seems to be cured sometimes by dropping the front panel (it hinges on a couple of screws), reseating the various connectors, and raising it again. You might try that before bringing out the scope and soldering iton. Bob K6DDX On Friday, April 17, 2020, 11:19:31 AM PDT, Roger Hoffman <sooline@...> wrote: I have a high serial number (12 mil) TS-940 that I just acquired and I have two questions ..... 1. The tuning rate is 3 KHz per revolution, not the 10 KHz that the manual states, and it doesn't change no matter how fast I spin the dial.... 2. Only every other band switch push button works....3.5 MHz, 10 MHz, 18 MHz, 24.5 MHz, and 29.0 MHz. I have reset the microprocessor, but no change.... Any ideas? Thanks, and 73.... Roger, WB9BXT. |
#280 hHi Roger, I had a similar problem, can't remember the exact details, but the band switching is done via a 4 bit binary coded digit which drives 1 of 10 decoder chips to raise and lower the respective band switching diodes. The digit is sent over 4 parallel wires and the least significant bit (the edge wire in one of the ribbon cables) was not making proper contact - hence only even numbers were transmitted. As Bob suggested, the fault cleared as soon as you hinged the front down, but returned when you raised it back up again - it took some finding, but it sounds very similar - happy tweaking! ALan G3UQW |
#281 Roger, I've serviced a number of TS-940S and here is the procedure I've used for accessing the front panel. It contains some details that will, hopefully, prevent you from accidentally doing any damage. *Do not trust the extendable feet, collapse them before proceeding. *Place at least a 1' x 2' board under the bottom feet to raise the front of the rig off the desk. Remove the top cover. Remove all screws from the bottom cover but do not remove it from the radio. Slide the radio forward in the bottom cover until the front panel clears the front edge of the bottom cover. There needs to be enough room for the front panel to pivot and lay flat on the table. Place a folded cotton towel under the front panel to protect the face while you are working on it. On both sides of the front panel remove the two (2) flat head screws in the sheet metal plate holding the front panel to the chassis. Loosen, but do not remove the round head screws. *T**he front panel MUST pivot from the rear round headed screws and NOT the countersunk screws that secure the cast front panel to the sheet metal ears.* *Look carefully at the outer edge of Switch Unit I (SSB slope tuning & CW VBT) to see that it will clear the chassis as the front panel is pivoted down. It may get caught on the chassis and be seriously damaged. Also, be sure to look to be sure you don’t pinch/pull any wires. *Pivot the front panel forward and down so that it rests on the towel. Good luck with your repair and please keep the group posted on your progress. Ken WA2LBI (email thread history removed by moderator) |
#282 OK, thanks to the folks that responded, I have fixed my Band Switch issue.....I found a partially inserted connector on the associated board. I pulled it and replugged it and all is well. Makes changing bands a whole lot easier!!!!!! Thanks all, 73, and stay healthy! Roger, WB9BXT (email thread history removed by moderator) |
#283 Check to see if you have the TS-940 Giehl chip installed. It allowed 4 different tuning steps. https://www.wb8bfs.com/kenwoodchip.html Mike KD9CK |
#284 |
#285 Have you physically looked to confirm the Geihl Eprom is installed? It is not stock. -- Clif Holland KA5IPF www.avvid.com |
#286 Cliff: toggle quoted messageShow quoted textI'm not very familiar with that chip...where would it be located? Thanks, and 73.... Roger, WB9BXT On Thursday, April 23, 2020, 09:42:44 AM EDT, Clif Holland <clif@...> wrote: Have you physically looked to confirm the Geihl Eprom is installed? It is not stock. -- Clif Holland KA5IPF www.avvid.com |
#287 it's on the digital board that i /think/ also has the piexx/if10 toggle quoted messageShow quoted textplugged into it.. -a On Thu, 23 Apr 2020 at 08:58, Roger Hoffman <sooline@...> wrote:
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#288 Found this with a google search in about a minute.. toggle quoted messageShow quoted textInstallation of Giehl chip: The Giehl chip replaces the IC2 chip in the Digital A Unit. Some TS-940 IC2 chips are soldered and some are in sockets. Chips that are soldered without a socket require extra care in removing the original and installing the Giehl chip. ----- Original Message ----- From: 'Adrian Chadd' <adrian.chadd@...> To: 'kw-ts940s' <kw-ts940s@groups.io> Sent: Thursday, April 23, 2020 5:40:37 PM Subject: Re: [kw-ts940s] TS-940 Questions it's on the digital board that i /think/ also has the piexx/if10 plugged into it.. -a On Thu, 23 Apr 2020 at 08:58, Roger Hoffman <sooline@...> wrote:
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#291 Hi Roger, toggle quoted messageShow quoted textyou can easily check if the Ghiel Chip is installed in your TS940: If you can temporarily change the frequency of a memory channel in MEMO mode, then you have the Ghiel Chip installed.With the Ghiel Chip also the main Vfo knob tuning rate is controlled by the MEMORY BANK switch located under the sliding top cover of the radio. 73 de Martin, IW3AUT Il giovedì 23 aprile 2020, 17:58:55 CEST, Roger Hoffman <sooline@...> ha scritto: Cliff: I'm not very familiar with that chip...where would it be located? Thanks, and 73.... Roger, WB9BXT On Thursday, April 23, 2020, 09:42:44 AM EDT, Clif Holland <clif@...> wrote: Have you physically looked to confirm the Geihl Eprom is installed? It is not stock. -- Clif Holland KA5IPF www.avvid.com |
#294 Another easy way to check for the Geihl IC. Do a reboot. If it comes up at 14.000.00 USB it is stock Kenwood. IIRC the Geihl IC come up at 10.100 I could be wrong but it doesn't come up at 14.100 -- Clif Holland KA5IPF www.avvid.com |
Kenwood Serial Number Lookup
Sep 09, 2015 Genuine Kenwood batteries: W09-0359-05 TS-940S LITHIUM BATTERY The table below shows many of the 3 volt dc coin type batteries you can use!! Here is the display after being removed and prior to battery replacement.
The Kenwood TS-940S/AT was manufactured at and after 1986. At the time Kenwood considered it their top of the line competition class HF radio until it was later surpassed by their newer model TS950DX.
The Kenwood TS-940S is the same as the TS-940SAT except without the automatic antenna tuner. The 'AT' after the S is for Antenna Tuner.
Features
From Kenwood product propaganda:
Competition class HF transceiver
TS-940S-the standard of performance by which all other transceivers are judged. Pushing the state of the art in HF transceiver design and construction, no one has been able to match the TS-940S in performance, value and reliability. The product reviews glow with superlatives, and the field -proven performance shows that the TS-940S is 'The Number One Rated HF Transceiver!'
- 100% duty cycle transmitter.
Kenwood specifies transmit duty cycle time, The TS-940S is guaranteed to operate at full power output for periods exceeding one hour 1 14.250 MHz. CW, HO watts.) Perfect for RTTY SSTV and other long-duration modes.
- Extremely stable phase locked loop (PLL) VFO, frequency accuracy is measured in parts per million!
- 1Operation
- 2Review
- 4Related
- 5Service
- 6External Resources
Operation
controls
FUNCTION switches
- T-FSET switch - Depress this switch to 'SPOT', or momentarily interchange reception frequency with transmission frequency. Frequency 'SPOTTING' is possible only in receive and is ineffective during transmission
- A/B - Selects the VFO or VFO B.
- SPLIT - For split frequency operations A-R, B-T OR B-R,A-T.
- A=B - During VFO operation, press this switch to equalize the frequency and mode of the idle VFO to that of the active VFO.
- F.LOCK - Press this switch to lock the VFO and BAND switches.
- VOICE - Announces the frequency when an optional VS-1 is installed inside the cabinet.
Review
some of the known issues
- LCD Sub Display not working
- Memory channel loses information
- Intermittent Transmit, all bands
- Intermittent Receive, all bands
- Internal antenna tuner not working
- Bad/cold solder joints
- RF Preamp FET incorrectly installed
production run improvements
Based on which production run the radio is from may determine what problems you will have. If you can power it up then down again and the S-meter slams to the right, it's the first production run and may have a number more problems than later runs where factory assembly defects were corrected.
Based on the serial number you can tell the year of manufacture. It is the first digit of the SN that is the year of manufacture. If the SN is 6xxxxx then it was made in 1986. I have a unit with the serial number 7100019 which makes it a 1987 production year which is still part of the first production run as its S-meter slams to the right when powered off. It also seems to exhibit many of the known issues that are well known for this model.
Quoted from N8YX, 'any folks opine that any serial number above 7 million is 'safe', while others swear that the magic number is 8 or even 9 million+.'
power supply
'The later version's IF board can be swapped into an earlier unit and this will cure many (problems). Also look into upgrading the power supply cooling arrangement. Citation from N8YX
The power supply fan operates on 12VDC. Sometimes when the OEM fan tests good on external power, it could be that under load the fan is not getting sufficient voltage from inside the unit. Under load it has been reported that the voltage measured on a meter dropps from 17v down to 3v. This relates to a problem with the AVR board. Modern computer fans can serve as excellent replacements in the fan is bad.
PLL Unlock
From a Kenwood TS-940S Service Bulletin 10/18/1985 - Some users of the TS-940S have reported a blanking of the display accompanied by a loss of transmit and receive. Readjustment of the PLL unit will correct this tendency.
Procedure:
On the PLL Unit
- Set the dial frequency for approximately 1.8Mhz (inside the band).
- Using an RF probe at TP #5 adjust L22, L23 and L24 for a maximum reading on the meter. You should see approximately 250mV.
- Adjustment of L24 will produce the greatest change, which may be up to 90 degrees from its present position.
Sub LCD Display Blank or Boxes
On the bottom right of the LCD Board thereis a black plastic momentary switch. I justpuched it once and it reset all the LCD parameters.VFO display, Clock, etc. That was it!
reference: http://www.eham.net/ehamforum/smf/index.php?topic=68286.0
Procedure verified.
Vacuum Fluorescent Display problems
maintenance
A semi-skilled tech should have no problem keeping one on the air. Pay close attention to the AVR pass-transistor cooling fan (or replace it). Most problems of an intermittent nature with a rig this old can be traced to questionable connectors on the various circuit boards. Resoldering them is a tedious job but aside from replacing memory batteries (or re-peaking the VCO tuning coils, if necessary) is usually all that's required in the way of maintenance (for the TS-940S transceiver.) Citation from N8YX
See the list of Kenwood Service Bulletins
Documentation Downloads
Service Manual, Individual Board Schematic Diagrams, and other Product Literature from Kenwood.
Kenwood Ts 850 Serial Numbers
Related
This radio uses slope detection, which is a way to receive an FM (or PM) signal on an AM receiver.
The cooling fan on the back is temperature sensor based rather than timer based, according to a HAM radio source online. It is a recommended modification to make it so the fan runs all the time, which is accomplished by jumping connector #13.
SSB slope tuning
In SSB slope tuning, one filter passband can be shifted up in frequency and the other filter passband can be shifted down in frequency, effectively narrowing the bandwidth of the combined filters. Basically you can narrow from either end and to what degree best helps to eliminate noise and near frequency interference.
An excellent article on How to maximize your receiver's effective selectivity written by ham radio operator Rob Kalmeijer covers the use of slope tuning.
compatible microphones
Microphones recommended in literature for the TS-940S.
- Kenwood MC-60A - upright desktop microphone
- Kenwood MC-42S - hand microphone with up/down
- Kenwood MC-80 and MC-85 - upright desktop amplified microphones
source: rg4wpw Microphone Connections
Kenwood Ts 950sdx Serial Numbers
The Kenwood MC-42S is an 8-pin 600 ohm dynamic mic with up/down buttons on the top.
Kenwood Ts 530s Production Dates
Kenwood mic pin-out:
- Pin 1 - Mic audio
- Pin 2 - PTT
- Pin 7 - Mic audio ground
- Pin 8 - PTT ground
Service
cooling fans
There are two of them. One for the voltage control and one on the finals. Both are in back of the unit but only one is visible without removal of case.Cooling fan: The cooling fan is connected to the AVR board. There is a thermister on the back panel inside. It can be removed so that the fans run continuous. This will burn up the OEM fans if ran continuous. Computer fans can run continuous. If the fan stops you will loose the AVR unit, very hard to find and now you have a door stop. The OEM fans are still around, but getting somewhat rare. It is better to replace them with computer fans, which are a lot less of a problem.
LCD Sub Display
If the LCD sub display starts to show garbage you can attempt a reset. The reset is a momentary button inside the unit, you will have to remove the case. So take off the top case and look at the board with a battery on it directly behind the LCD. Right of the battery and in the bottom corner of the board is the black reset button. Use a nonconductive tool to press it and reset the sub display.
External Resources
SM2YER Goran product manuals and technical schematics for the TS-940S/AT - I noted that the Service Manual PDF on his site is not a good PDF.
This unit has been out of production for many years. Get an idea of the used market prices by looking at these Kenwood TS-940SAT classified on Universal Radio Inc.
KENWOOD TS-940S/AT PLL Wax Woes: Almost everyone who owns a Kenwood TS-940, TS-440 and a few select other transceivers or even the R-5000 receiver will have heard, or experienced, the dreaded PLL wax potting curse.
RF Preamp FET mod/repair to improve receive sensitivity; Kenwood TS-940 Assembly Error Corrections
K3TEN Electronics Technical Information-Kenwood TS-940s - many pictures of boards and components.
Competent Service / Repair
David Lyndon aka Old Ham Dave - (AK4AA) repair, align, and refurbish.
- NORTH CAROLINA
Clif Holland AVVid - (KA5IPF) repair of most Kenwood Amateur Radio Equipment
- TEXAS
K3TEN Electronics (unverified) Amateur Radio Repair & Restoration
- NEW JERSEY