Phillips 520FL3603D/F7 Power Supply Dead

[karatzdi]

Re: Phillips 520FL3603D/F7 Power Supply Dead

WHAT IS WRONG WITH THE POWER SUPPLY??
Have you checked ANY voltages ?

The resistor is ok, you are also measuring your meter lead resistance when checking the resistor. R929 is not critical it is used like a fuse, so if it does not check OPEN, it is good.

This is the standby circuit, is it working or not? Do you have standby voltage or not?
What is the voltage measured ACROSS C911, VCC Voltage

Hello..Sorry I completely missed your questions here !.

Ok the problem is that the TV has no power. Not even getting into the Standby mode when turned on from the power switch. It has no reaction from the Remote control, because the standby circuit is not working because the ZD905 got shorted out the 1ohms resistor got a bit hot and deformed / altered its value. I am not sure about the luck of IC901. There was a quote or reply to me that since ZD905 is now burned, IC901 is compromised. Therefore I did not deem necessary to plug it on mains and test.

Yes I understood that the criticality of R929 is a fuse. I believe though as a matter of good practise that these parts must be replaced before plugged onto mains.

2.1ohms it is the parts value as it is measured out of circuit.

No Nothing works cause for caution reasons I did not plug it on the Mains. The IC will be available 05/23 on Mouser.

So hence no voltages have been measured yet.

If you guys insist to plug it I will go for it. I just need to be extra cautious. I have no variac or isolator transformer in my lab yet. The mains voltage here is 240v.

Thank you very much R-J. ! Appreciate the effort from all in this group

[karatzdi]

Re: Phillips 520FL3603D/F7 Power Supply Dead

Now it is clear that the positional numbers of the components do not match.

Iotas, thank you very much for all efforts. It seems that this diagram is very close to what I have on the PCB am currently trying to fix. Actually ZD905 is located physically and connected to Ground (one leg), whilst the other is located to the last 2MΩ resistor. The locations are indeed different. But not the physical locations of the parts on the PCB.

May be because you have schematics of a different revision from my board.
So the Zener is 7.5v.. I got one for 10v on the PCB. Not SMD though

Why dont you send us the complete schematic on the forum so everyone can have it ! I mean its the purpose of this forum !!


Thanks

[lotas]

Re: Phillips 520FL3603D/F7 Power Supply Dead

Iotas, thank you very much for all efforts. It seems that this diagram is very close to what I have on the PCB am currently trying to fix. Actually ZD905 is located physically and connected to Ground (one leg), whilst the other is located to the last 2MΩ resistor. The locations are indeed different. But not the physical locations of the parts on the PCB.

May be because you have schematics of a different revision from my board.
So the Zener is 7.5v.. I got one for 10v on the PCB. Not SMD though

Why dont you send us the complete schematic on the forum so everyone can have it ! I mean its the purpose of this forum !!


Thanks

No problem, it's freely available.

[R_J]

Re: Phillips 520FL3603D/F7 Power Supply Dead

There is no way R929 got hot and deformed, if it does not measure OPEN, it is good, ZD905 shorting would not cause the resistor to get hot.
I suspect there was a voltage spike that caused zd905 to short, replacing the zener with the correct value should restore the standby circuit.
You can use an incandescent lamp (60~100watt rated at your line voltage) in series with the ac line to limit the current to the power supply to check if it is drawing too much current.

2.1ohms it is the parts value as it is measured out of circuit

What resistance do you measure when you short the meter leads together on you meter?

[karatzdi]

Re: Phillips 520FL3603D/F7 Power Supply Dead

There is no way R929 got hot and deformed, if it does not measure OPEN, it is good, ZD905 shorting would not cause the resistor to get hot.
I suspect there was a voltage spike that caused zd905 to short, replacing the zener with the correct value should restore the standby circuit.
You can use an incandescent lamp (60~100watt rated at your line voltage) in series with the ac line to limit the current to the power supply to check if it is drawing too much current.
What resistance do you measure when you short the meter leads together on you meter?

Thanks for input there R_J. The Resistance of the test leads is 0.2 to 0.21 ohms when shorted.