I got involved in looking into troubles for a "friend of a friend' .I
have heretofore always turned down large projection sets.As I am a
retired ex service man and have only myself,; thus the reason for not
working on any of them.
This set uses the PTK195MIB CHASSIS and is Model P52927. I have
literature on the CTC195 Chassis, but find no listing on the above model
# or Chassis #, but I believe it uses for its main power supply a
similar supply that is used in the CTC195.
Having said all of the above to expain my dilema. I found the
following symptoms and am wondering if anyone has seen similar
symptoms.
The set turns on when cold, then runs perfectly for 5 or 10 minutes
, then goes into a blinking on and off mode for a short while, then
turns off altogether. I noticed that during the on and off sequence that
the 3 color tubes turn on and off as does the sound. These bursts of on
and off are about 1 or 2 seconds apart.
I have worked on 195 chassis and have repaired complete breakdowns.
Mostly they were completly inoperative and troubleshooting was not hard.
What I was wondering is, has anyone out there had this intermittent
trouble?
My guess would be break down of Caps in the primary power supply,
but working on 52" set in the users home is almost impossible unless one
has a definite idea what the trouble and what parts to bring.
Thanks for taking the time for reading this, and responding with
any suggestions.
Thanks
Tom
PS I had my trusty ESR tester and DVM with me but did not pull the
chassis at the time. Too much of a hassel
on the living room floor.

Start by getting the error codes and clearing them.
The ptk195 is known for coolant leakage and conductive glue underneath
surface mount capacitors, both of which can cause the given symptom.

Depending on serial number, that is a pile of service bulletin updates
that may address the issue.

Virtually every single of the hundreds of ptk195 chassis I have seen
had an intermittent problem.