Thank you.......I appreciate the info. It is interesting that semiconductors
would degrade in that manner, unless they were being run near their design
limits. If this is the case, the parameters were not derated properly.
I ran into the same thing with the Lowe receivers. They are using a 4569 to
divide the uP clock down to the BFO injection frequencies. Every so often,
these chips fail when brought up to operating temperature. Aside from the
dense plated through holes, these radios aren't nearly as bad to service as
that 6800 is. Anyway, it did turn out that the trimmer was indeed cracked. I
have repaired the unit and it is going back to the owner. It was the most
incredible nightmare to repair, but I was able to fix it.
The fellow that I made the deal with is giving me a Grundig 3400 as a
consolation prize. That radio is a little bit bigger than what I would
normally use, but it is good trading material.

Pete

"C.R. Kuijer" wrote in message
...
Are you sure?
Pse check the amplitude on both inputs of the PLL circuit.
In both cases when locked and when lock is lost.
About 50% of the 2SC930 in this radio will have 50% reduced hFE.

Pete KE9OA wrote:
I found the problem with the radio. TC8, the trimmer capacitor for the low
end VCO range was cracked and wouldn't tune.

I've seen that before.. cracked coils and trimmers are the signs
of a twirler,someone with tools but little skills with regard to
rf alignment. was the trimmer accessable before dismantling?


I looked at the parts list and all that was given was a Sony part
number.......no value in pF.
What a useless manual! At least it was only 25 dollars. If I knew what
value this cap was supposed to be, I would throw in a microwave trimmer
cap.....that is, if I could get all of that plastic for the bandswitching
mechanism out of the way.

Pete

"Pete KE9OA" wrote in message
...
I received the service manual. Now, on to the repair.............

Pete

"BDK" wrote in message
...
In article ,
says...
All of them wimmins are gullible to computer spam and computers
viruses.You would think they have at least half a brain.But there is
nothing between their ears but peckers.
cuhulin




Nah, just as many guys fall for it, she's just the only one I know of
that fell for the messages and the credit card stuff.

BDK

I've seen that before.. cracked coils and trimmers are the signs
of a twirler,someone with tools but little skills with regard to
rf alignment. was the trimmer accessable before dismantling?

The trimmer is only accessable once you remove the chassis from the cabinet.
It wasn't a matter of somebody destroying it..it didn't need any help. It
just fell apart over the years. I did replace the trimmer, and the alignment
notes stated that an external frequency counter could be used if the radio's
digital display was defective. Of course, the internal display wasn't
defective, but Sony's alignment notes are utterly useless. They tell you to
disable the high frequency PLL.......once you do this, the system goes out
of lock and the internal display shows what appears to be the preset
frequency.
Ok..............I decided to use an external frequency counter. The only
problem here is that the useless service manual doesn't show where to hook
up the counter.
The radio went back to its owner, and a Grundig 3400 was traded to me
instead. I am working on the Grundig unit now. I just got through cleaning
the I.F. bandwidth switch and adjusting the indexing mechanism for the SW
bands.
One thing I can say after comparing the innards to my Grundig
TR-6001.....the mechanical construction of the indexing mechanism on the
TR-6001 is much better than the 3400. Instead of using these leaves sticking
out from each of the band range modules the way it is done on the 3400, the
6001 has either gold plated or brass rivets that make contact with the leaf
springs instead.
A much more reliable radio.......I think that the 6000 series was the best
of their whole model line, although the 3400 was still made in Germany, it
still used ERO polypropolene audio capacitors, and it still used a
Variometer that was mechanically coupled to the main 2-gang tuning capacitor
to add that extra 3rd gand, so it wasn't completely without its good points.
Once I finish it up, I will play with it for awhile, and then trade it off.

Pete