Kenwood TS850S

 Maintaining the Kenwood TS850SAT.


This device supports

  • Internal ATU
  • CW memorys
  • Dual VFO
  • Internal keyer
  • CAT interface. ( Search ebay for sjgwilliam)


Type: Amateur HF transceiver
Frequency range: TX: 10-160 m + WARC RX: 0.1-30 MHz
RF Power output: Max 100 W
Voltage: 13.8 VDC
Current drain: RX: ? A TX: 20.5 A
Impedance: 50 ohms, SO-239
Dimensions (W*H*D): 330*120*334 mm
Weight: 11 Kg
Manufactured: 19xx-19xx (Discontinued)
Other: 100 memories New price 1992 in Sweden: 18894:- SEK


The main issues appear to be relate to capacitors failing.The CAR unit has signs of the capacitors leaking.

Could have been much worse.  The dialectic has not spread among the pins of the 6331’s.

Capacitor Kits –

The ATU requires a drop of oil as can hear it operating.

02042015 – CAR Unit repair.

The replacement capacitor kit arrived from Germany. I had not addressed straight away as big days at work so waited until Easter.

There were several activations planned for Friday and  a 80m QRP CW hour contest Easter Saturday night.

OK this device is not QRP. I can adjust the power down and having a good run with CW. We are out Saturday so decided to address Thursday night.

Watched a couple of uTube videos of others completing this repair then got the device on the kitchen table and set about replacing the capacitors.


View before cleaning up. You can see the leaked dialectic .

Removed the capacitors. Several came off as soon as I touched them. This was not a good sign, obviously there was was more damage then expected. Cleaned the dialetic with a fibreglass pen then washed with Isopropyl alcohol. This was a slow process as being careful not to damage the tracks. In the end there was only one track that was damaged and missing.


After removing caps and cleaning. Below is the damaged track


The replacement caps had longer leads then the original devices so able to bridge the span with no issues.

Useing solder paster I place a small dot on each track, positioned the caps then soldered with the fine pencil topped soldering iron. Replacing the caps took little time and after inspecting the results put the unit back in the radio.

Worked first time and as it was thursday night went looking for the SOTA CW net and found Tony VK3CAT. 

All good. 

3 responses to “Kenwood TS850S”

  1. Malcolm Nicklin VK6HY says :

    G’day OM I had the same trouble not using the rig for a number of years the TX LED was glowing and it would only RX on FM. The caps had gone on the Carrier board and taking most of the tracks around them off the board. It was not possible to re fit SMC so dedicated caps had to be fixed in place and a blob of hot glue to stop them moving and pulling the remaining tracks off the board.

    Pleased to say the old 1992 rig is working well again. 73 s Malc VK6HY Perth WA

    • Allen VK3ARH says :

      Hi Malcolm,

      Very happy with the TS-850. Know she is old but just works as expected and I find easy to use. Got the capacitors set ready to replace as problems surface but after addressing the carrier board and giving her a clean, no issues.

      Will be using this device for a while.


  2. Noel says :

    Hi, I couldn’t get the original CAR board working again so I bought an updated CAR board from a guy in the Ukraine who makes a replacement board for the 850. It’s a bit expensive but works a treat. Took a few weeks to come in but an easy upgrade and worked really well.Now my 850 is back on the air 🙂 VK4ETI

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