RCA P46730WK PTK169PCA flicker in video, tuner
 

This one came in with intermittent power, low B+ when not turning on. Found
the 39 uF cap on the chopper bad and the 2.2uF cap on the controller IC high
in ESR. OK, that was pretty straightforward. Now it runs ok, except that
it starts to flicker when it heats up. When it does, all of the supplies
that I have been able to find seem rock solid. Cooling the obvious stuff
has no effect. The set previously was serviced for the brown goo from the
rubber spacers and the boards were thoroughly cleaned. A few caps in the
PIP circuit were changed at that time, and they all check ok now. Now the
strange part. Once it starts to flicker, if I turn the set off and back on,
it will be fine and never starts again until the set is off for a long while
and restarted. When it starts it is fine, then starts to flicker after
running up to normal temp. Seems like a cap, but have not been able to find
the one that is acting up.

Checked the Intrepid, TechAssist files and archives, plus a few more sites
and no luck excep some unstable brightness tips for CR2901 but it is not
thermally sensitive. Haven't checked for signal there yet as the unit is
now running ok.

Any ideas?

Leonard

RCA P46730WK PTK169PCA flicker in video, tuner
 

With the RCA CTC 169 Projo's, you must, by habit, always
change the TEA2261 PWM IC, & all caps around it! CTC169-
Kit. Also check for coolant leaks. Sometimes you will find black
residue on the bottom of the main pcb, caused by leaky caps. Sky.

RCA P46730WK PTK169PCA flicker in video, tuner
 

Thanks for the attempt at help. However, I don't agree that the TEA2261
always needs to be changed. We fix a lot more of them that just need the
three caps that typically go bad. In this case, however, the PS output is
solid, with no changes in dc or ripple when the symptom occurs. The boards
have been checked for coolant very carefully, as for leaky caps. In fact,
most of the likely suspect caps have been tested or changed. Obvioulsly we
haven't got he right one yet...

Leonard

"Skype_man" wrote in message
.. .
With the RCA CTC 169 Projo's, you must, by habit, always
change the TEA2261 PWM IC, & all caps around it! CTC169-
Kit. Also check for coolant leaks. Sometimes you will find black
residue on the bottom of the main pcb, caused by leaky caps. Sky.

RCA P46730WK PTK169PCA flicker in video, tuner
 

Leonard Caillouet wrote:
However, I don't agree that the TEA2261
always needs to be changed. We fix a lot more of them that just need the
three caps that typically go bad.

Same here, the controller is either good or bad in my experience

Do you have a PIP module to swap? If you don't have one, I might have
one somewhere.

John

RCA P46730WK PTK169PCA flicker in video, tuner
 

Actually, John, it looks like the problem is occuring only on the tuner. I
thought I saw it on the composite input but it seems ok now. Additionally,
it seems sensitive to color. A gray scale pattern does not flicker.
Various combinations of R,G, & B rasters affect it differently. Would be
interesting and pretty easy to troubleshoot knowing that now but the client
will not spend any more money or time on this old unit and uses composite
inputs with a cable converter anyway.

Thanks for the help.

Leonard

"John-Del" wrote in message
oups.com...

Leonard Caillouet wrote:
However, I don't agree that the TEA2261
always needs to be changed. We fix a lot more of them that just need the
three caps that typically go bad.

Same here, the controller is either good or bad in my experience

Do you have a PIP module to swap? If you don't have one, I might have
one somewhere.

John

RCA P46730WK PTK169PCA flicker in video, tuner
 

Leonard Caillouet wrote:
Actually, John, it looks like the problem is occuring only on the tuner. I
thought I saw it on the composite input but it seems ok now. Additionally,
it seems sensitive to color.


Hey! Remember the old CTC131\2s? I remember an odd symptom where the
TV would start to flicker as it warmed up. It drove me nuts, but it
turned out that slightly tweaking the 4.5mhz traps would clean it up.
I don't know if the 169 has the same traps, but it's worth a look.

John