[Kenwood] TS850S no Tx output

[Michel Spelier]

Dear all,
I'm looking for advice regarding this excellent transceiver.

After 5 years of successful operation, as IF rig for my 2m transverter, it suddenly stopped delivering its +10dBm or so output power. After some investigation, I decided to turn the rig into the local service shop.

It just returned from the local dealer stating that the problem, with high probability, was originating from the digital board behind the display.
They explained...they started rewiring it to a regular HF-rig and retuned the VCO's and more, to find out it did deliver its regular 100W but too briefly, 60ms or so. Which is very brief and not leaving, very much of a chance to find the cause...
Apparently, some processor returned a Tx-inhibit signal to deliver its awaited output power continuously.
So they logged into the Kenwood Eu and Japan stock but the big digital board appears to be out-of-stock.

For the sake of completiness, this TS850S being of US-origin, developed two years ago, the well-documented .............in-the-display-syndrome, which was corrected by Kenwood-Belgium, since. 

So being unsure how to proceed, I post this question. Anyone seen, heard this problem? A cure?
Should I bring it in into another shop?
Should I strip it down (it contains some filters and the ATU) and sell the rig which is still fully functional as Rx to a SWL or is there interest by a skilled person with instruments to find the cause?

Thanks for any advice,

Michel, ON7EH