Sony KPR-4110 - HV comes up and shuts down constantly.

[Tyrone Park]

When this set is turned on HV comes up and then goes down in a
repeated cycle. There is no audio as well. I do not have a service
manual for this set and this is the first one of these that I have
seen. It appears that when the crt's illuminate the set shuts down.
Using the video input mode with no input, the set would constantly
pulse for a short while until the pulsing became minimal to then not
pulsing at all. Sort of like a cap is weak or something. Have anyone
seen this problem before? Any response is appreciated!

 

[Andy Cuffe]

When this set is turned on HV comes up and then goes down in a
repeated cycle. There is no audio as well. I do not have a service
manual for this set and this is the first one of these that I have
seen. It appears that when the crt's illuminate the set shuts down.
Using the video input mode with no input, the set would constantly
pulse for a short while until the pulsing became minimal to then not
pulsing at all. Sort of like a cap is weak or something. Have anyone
seen this problem before? Any response is appreciated!

If this is the set I'm thinking of start by checking all the series
inductors on the flyback secondaries. I've seen several of these with
an open inductor for no reason. Also, check for bad soldering and
blown fuses on the convergence board. Check all the power supply caps
with an ESR meter. If you don't have an ESR meter start by replacing
any caps in hot areas of the board.

Have you looked in the lenses for cloudy coolant? This set uses CRTs
that are glued together which makes it very difficult to change the
coolant. If it has bad coolant, I would junk it. It's a long and
messy job to change the coolant in all 3 tubes.
Andy Cuffe
[email protected]

 

[JURB6006]

I've seen this caused by bad convergence ICs. If you unplug the convergence
board I believe you don't get video, but it won't cycle.

Incedentally the coolant is very hard to change in those. I've done it and
gotten real good results, but it is a huge PITA.

If you can get them, STK4191 is the upgrade from the STK4121s the set came
with.

JURB

 

[ezwizzard]

When this set is turned on HV comes up and then goes down in a
repeated cycle. There is no audio as well. I do not have a service
manual for this set and this is the first one of these that I have
seen. It appears that when the crt's illuminate the set shuts down.
Using the video input mode with no input, the set would constantly
pulse for a short while until the pulsing became minimal to then not
pulsing at all. Sort of like a cap is weak or something. Have anyone
seen this problem before? Any response is appreciated!

Hi, check solder connection on 5.6uh inductor L1-407-690-00