No power, no led light. Rear projection tv

[Echo26]

Badly needed help and had been troubleshooting for 4days. I have a Sony Kpf43m91 rear projection tv, i gues was built jn 2007 . Everything's fine until we heard a hiss and a pop on it, opened and saw a 22uf cap blown. I replaced it with a new one, still no power or led light response. Cant even get into service mode. I have the service manual and schematic , found no voltages on standby and low voltage on the relay line. Primary Power supply is active and properly supplies 240v.

 

[Harald Kapp]

Fuses?

 

[Echo26]

Fuses?

No blown fuses. Had it checked first, i thought the same thing. But its actually fine. Cord was fine. Primary powersupply is active.

 

[shrtrnd]

Trace connections to your blown cap. You probably lost a semiconductor and saw a current surge through that cap.

 

[Echo26]

Trace connections to your blown cap. You probably lost a semiconductor and saw a current surge through that cap.

I'll chekc it out . Does it really affect the secondary power supply? The blown cap was around the horizontal section.

 

[shrtrnd]

Let me think.
Your fuses are OK (I hope you found all of them).
You heard a hiss and a pop, and found a blown 22ufd cap, which you replaced.
But you still have no power and no LED light.
Yes, it would seem to me that something else in the 22ufd cap circuit is not quite right.
I would be looking for a component that allowed smoke to escape from your 22ufd cap, burned 'open-circuit' now, and is therefore denying voltage to the affected circuit.
Good luck.

 

[Echo26]

Seems

Let me think.
Your fuses are OK (I hope you found all of them).
You heard a hiss and a pop, and found a blown 22ufd cap, which you replaced.
But you still have no power and no LED light.
Yes, it would seem to me that something else in the 22ufd cap circuit is not quite right.
I would be looking for a component that allowed smoke to escape from your 22ufd cap, burned 'open-circuit' now, and is therefore denying voltage to the affected circuit.
Good luck.

yeah I mean, I know a bit on voltage acheckin and trouble shooting but that cap is too far from the h.out of the yoke, and the primary and secondary supply was on the second board. I'll have to check it out again. These TV's are so complicated not just like regular Crt tvs. I'm still waiting for my new multi tester, i have blown my old one.

 

[shrtrnd]

Be careful in there. Not worth a trip the the hospital if you're unfamiliar with this circuit.

 

[Echo26]

Be careful in there. Not worth a trip the the hospital if you're unfamiliar with this circuit.

Yeah, i remember putting always one hand on the pocket. Seeing a 30kv dc in a schematic is mundane.