of the Sony ICF-6800W - nr 5 (1979)
I bought this ICF-6800W from the original owner. Problems:
- mode switch not working
- preselector not really functioning (some response)
- no meter response
- on SW no counter movement when spinning the dial
- various screws missing (front panel loose...)
- the usual dirt and small scratches
So a bit of a gamble since for sure somebody had already attempted
repairs. From talking with the owner, the Sony service center had had a
go at it, but was not able to repair.
a. Clean with water and soap (I dont like to work on a dirty radio).
b. Start disassembly
Somebody did not bother to put the MW shield cover back on:
Bits and pieces:
The folks attempting repair were close to the problem. The technique is
a bit strange though... to get access to the problem area, they just
melted the plastic assembly with a soldering iron!
I like to work on the radio in this position: it is fully functional, and the PCB is accessible for measurment:
Same -- other angle:
c. Contact clean all switches and pots.
d. So now we are ready for the PLL problem: see Technical Note 1. In
this case Q32 and Q33 have been replaced. because of the melting
excercise above I put the replacement transistors on the PCB side of
Replacing these gave a nice functioning PLL, with strong inputs to IC2.
e. Other problems.
For the mode switch, the problem is mostly just mechanical... the screw needs to be adjusted correctly and fixed well.
The meter was fully functional, but the wires at the underside of the
lamp board were sheared off - this is a weak point - take care during
The preselector was indeed functioning, but I took me awhile to find
out what had happened... somebody did the stringing so that it was
reversed... rightmost position was low bands... the joy of vintage
repair: you never start from a consistent state.
Some hints for restringing the FM dial cord since this is not in the service manual.
f. Alignment as per service manual
3. OPEN ISSUES
About 2 hours cleaning, 5 hours repair and 1 hour alignment.
Sensivity: MDS at 14,1 MHz -134dBm using the signal generator on the PL input.
Good service documentation can be found on mods.dk. But i am still
looking for GOOD scans of the PCB. Anybody with a service manual
Serial number 177?? (unreadable).