Tv SMPS trips on start up with Main Smoothing cap in???

[tvtech]

And, like you, I'm now fresh out of ideas Either something that shouldn't is pulling pin 1 high, or something that should isn't pulling pin 1 low. Can't see any other possibility; unless the chip itself is flakey.

Something interesting happened last night. A member here who is familiar with these sets and who has also battled with this PSU PM'd and gave me the following tip "Also change out C810 with a new one".

I cant access the set now because it is Weekend here and the shop is closed. But I will find time next Week to put it back on my bench and try his advise.

Holding thumbs here

Regards,
tvtech

 

[alec_t]

Good luck with the cap swap.
Also worth swapping the 220p 2kV cap (Cxxx) across pins 2 and 3? If that's leaky at high volts it might explain things.
On the subject of tracking, does it always leave visible evidence (e.g. darkening of pcb)? It's something I've no practical experience of.

 

[tvtech]

Good luck with the cap swap.
On the subject of tracking, does it always leave visible evidence (scorching of pcb etc)? It's something I've no practical experience of.

Hi Alec

Years back, there were some original Telefunken sets that really liked to track/arc/burn the PCB around the LOPTX (Line Output Transformer) area.
Especially in coastal areas.

But it happens even in sets these days. Mostly due to cockroach wee or other fluid based problems.....like many people think it is cool to put a vase with fresh flowers and water on top of the TV...guess what happens next.......

Arcing is a problem on some sets...even these days. Evidence of tracking/arcing is pretty easy though. On a clean board you can spot it a mile away.

But you know what.....C810 maybe having gone slightly leaky would explain all. Check the diagram again....

Best Regards,
tvtech

 

[alec_t]

Mostly due to cockroach wee

Faults due to that are fortunately uncommon in the UK

 

[diy didi]

Any luck so far tvtech?

 

[tvtech]

Any luck so far tvtech?

Hi Buddy

Not yet. I have not put the set back on my bench again. Way too much other new work coming in that I have to keep up with

I am trying for tomorrow or Friday though. I will let you know what happens.

Good to see you are from South Africa here too on this brilliant Forum.

Regards,
tvtech