Fault check opto-transistor

[pacmyc]

While troubleshooting my PSU for Philips 42PFL7403D I ran into the optotransistors 7202 and 7214.
They are named TCET1102. Im looking at schematics for this component and Im trying to figure out
how I can check if they are working as they should. When I compare them with a ohm-meter I get different readings on them..

As I understand there's a diod between pin 1 and 2. So, it should lead current from pin 1 from pin 2. Also it should open for current from pin 4 to pin 3 while current goes from 1 to 2. Right?
But, if there's no current at all on pin 1 and 2, should pin 3 and 4 be completely isolated?

[Keith]

Hi

Data sheet attached

Keith

[Turnip]

Hi Pac,

Thought is, after a serious PS failure, just change 'em after replacing the blown bits - they're cheap, and if duff, will poop your repaired PS due to lack of voltage feedback.

Otherwise - what's the PS part number and problem ?  - Chris.

[pacmyc]

Hi.
I dont know how serious the PSU failure is, as the TV sometimes still work.
It might have to do with the surrounding temperature to do, it feels like it works better when it's a little bit colder.

The itemnumber for PSU in the servicemanual is 3104 328 52761,
but the number printed on the PSU is 3104 328 52762.

[Turnip]

Hi Pac,

By 'Serious failure'  I meant mains fuse O/C, popped power Fets and drive chips cremated where feedback optos connected to drive chips also become duff.

Seems in your case different, especially as dodgy caps need high temperatures to function but your PS prefers cold conditions - curious.

Not yet met your PS - Chris.