RCA CTC203CA5,( model F36669) Brightness and tuning problem

[Lenny]

The customer who brought this set in said that for the past month
intermiitently he would see about four inches of black,(whether it was
compressed or just like a blanking problem I don't know) appear on the
top of the picture. This was sometimes accompanied by "popping"
noises. Then the other day it just came on very dark and now its dark
all the time. I looked it over and did not see any black come down
from the top as he had described but I did notice that although the
screen control has no effect on the raster however the brightness does
somewhat. The OSD looks fairly normal however at one point it too
dimmed and looked smeared but in turning the set on and off a number
of times during the day, I have not seen this particular smearing
repeated. so i don't know what thats all about either.
The other strange thing I have noticed is that although the channel
numbers display when attwmpting to change channels the set will only
receive channel three. I went into the menu looking for an
"autoprogram" of sorts and I found a screen to set up a VCR to channel
three etc, but no autoprogram. This channel three only problem could
have been an old one as the customer says he only uses channel three
with his cable box. I think I hear this one barking but I can't be
certain. Does anyone have any idea what these symptoms could possibly
indicate? Thanks very much. Lenny Stein, Barlen Electronics.

 

[dkuhajda]

The Channel 3 issue is a user setup problem in the TV Guide menu, they have
it set to work with a cable box.

The remaining issues will need considerable time and effort to duplicate.
Without a DSO it may not be practical to repair due to the labor time
involved and I am sure the customer may not want to leave the set in the
shop for a couple/few months while the problem is tracked down.

Be very honest up front with the customer about the nature of the failure
and the expected time required to repair an issue like this one.

Assuming it is not obvious solder connections (do not forget to pull the
base drive coil) you likely have conductive glue underneath some surface
mount component, probably somewhere on the clock and data lines..

David