SERVICE MANUAL & SERIAL NUMBERS.The Kenwood TS-940S/AT was manufactured at and after 1986. From a passionate Kenwood TS-940 owner. TS-940Ss in the serial number range of KENWOOD TS-940 PAGE Version 2: 4 April 2005, Version 3: 25 April 2005. Coverage: TS 940 covers 160 to 10. It has many features, including the following: Interference reduction: Enjoy the combination of dynamic interference reduction circuits and a high range receiver for quality transmitter design to get your signal through. The Kenwood TS 940 is a dynamic radio transceiver for the serious amateur radio operator.
![]() Kenwood Ts 940S S Serial Number Range Of![]() A=B - During VFO operation, press this switch to equalize the frequency and mode of the idle VFO to that of the active VFO. SPLIT - For split frequency operations A-R, B-T OR B-R,A-T. Frequency "SPOTTING" is possible only in receive and is ineffective during transmission 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. If the SN is 6xxxxx then it was made in 1986. It is the first digit of the SN that is the year of manufacture. 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. VOICE - Announces the frequency when an optional VS-1 is installed inside the cabinet.Based on which production run the radio is from may determine what problems you will have. Modern computer fans can serve as excellent replacements in the fan is bad.From a Kenwood TS-940S Service Bulletin - Some users of the TS-940S have reported a blanking of the display accompanied by a loss of transmit and receive. This relates to a problem with the AVR board. Under load it has been reported that the voltage measured on a meter dropps from 17v down to 3v. 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. Citation from N8YXThe power supply fan operates on 12VDC. Also look into upgrading the power supply cooling arrangement. Is mac bettr for cadPay close attention to the AVR pass-transistor cooling fan (or replace it). I justPuched it once and it reset all the LCD parameters.Vacuum Fluorescent Display problems maintenanceA semi-skilled tech should have no problem keeping one on the air. Adjustment of L24 will produce the greatest change, which may be up to 90 degrees from its present position.On the bottom right of the LCD Board thereIs a black plastic momentary switch. You should see approximately 250mV. Using an RF probe at TP #5 adjust L22, L23 and L24 for a maximum reading on the meter. Set the dial frequency for approximately 1.8Mhz (inside the band). It is a recommended modification to make it so the fan runs all the time, which is accomplished by jumping connector #13.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. TS-940S Technical Information (scanned)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. RF Unit, LPF Unit, Final Unit schematics Digital Unit, Switch Unit, RIT Encoder Unit schematics 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 N8YXSee the list of Kenwood Service BulletinsService Manual, Individual Board Schematic Diagrams, and other Product Literature from Kenwood. There is a thermister on the back panel inside. 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. One for the voltage control and one on the finals. Kenwood MC-80 and MC-85 - upright desktop amplified microphonesThe Kenwood MC-42S is an 8-pin 600 ohm dynamic mic with up/down buttons on the top.There are two of them. Kenwood MC-42S - hand microphone with up/down Kenwood MC-60A - upright desktop microphone If the fan stops you will loose the AVR unit, very hard to find and now you have a door stop. Computer fans can run continuous. This will burn up the OEM fans if ran continuous. 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 CorrectionsK3TEN Electronics Technical Information-Kenwood TS-940s - many pictures of boards and components.David Lyndon aka Old Ham Dave - (AK4AA) repair, align, and refurbish. Use a nonconductive tool to press it and reset the sub display.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. Right of the battery and in the bottom corner of the board is the black reset button. So take off the top case and look at the board with a battery on it directly behind the LCD. The reset is a momentary button inside the unit, you will have to remove the case. It is better to replace them with computer fans, which are a lot less of a problem.If the LCD sub display starts to show garbage you can attempt a reset.
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