Typically, a couple of transistors in the PLL chain lose gain over the years
/ decades. causing the problem that you are experiencing. I've got the
later "orange" model, S/N 34000. It seems that the later units don't have
this problem. I don't know if Sony had a bad batch of transistors, or if
they changed vendors for these devices.
It is quite a job to take the unit apart and get at those transistors, but I
don't have the expertise required with this unit. There was a fellow in
Norway, Sweden, or Denmark that had a website detailing this repair.
Basically, the PLL is very similar to the National HRO-500 and the Galaxy
R-530 / 1530 series. It isn't very complicated, but just getting at the
faulty devices is the major problem.
I hope it works out for you.

Pete

"Microvolt" wrote in message
...
I have the "white" version of the 6800. Appears to receive OK,
however on shortwave (only) it doesn't tune, and the digital counter
won't increment/decrement. Mediumwave is fine. The dial cord and
mechanical assemblies appear to function OK, and all contract switches
have been cleaned. There are some sealed metal shielding areas that
look painful to access, and reluctant to go that far if not needed.
The service manual isn't a lot of help.

Does anyone have experience of this particular problem with this
receiver?


Thanks.