VESTEL Power Board

Hi
I have a VESTEL 17 IPS62 ver2 Power Board from a Flat Screen TV , I did a test of 3 UF 5402 Diodes and one was faulty, so I changed the 3, still not working , there is a power light on ! .

So what I am wanting is, what readings should I be getting on the 20pin output connector CN2 , and where do I take the readings from ( ie ground to each pin ! ) am attaching a schematic for the Board .

cheers
Spike

OK, this is a serious design flaw in the Vestel sets (and always has been), they parallel three diodes without any series resistors, so obviously one overheats and goes S/C. Changing all three diodes, using ones from the same batch (or at last out of the same bag) cures the problem.

As the power light is ON, it looks to be working - have you tried turning the set ON, as it will power up in standby and you will need to turn it ON with the remote, or the buttons on the set.

If you're measuring voltages you measure from chassis - and easist place to measure is the cathodes of the three diodes you've just replaced. Anything else should be obvious from the circuit diagram, but I've repaired a LOT of these sets, replace the three diodes and they work - every time!.

Yes , did change them all , and you are correct it did go into standby and then you have to switch it again with remote , working fine now , thanks for your message , another item not going to the tip , hurrah .

cheers
Spike

spike47 said:

Yes , did change them all , and you are correct it did go into standby and then you have to switch it again with remote , working fine now , thanks for your message , another item not going to the tip , hurrah .

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It's really the main thing that goes wrong with them, and as I said it's such an obvious design defect.

Mind you, it does mean you can pick them up for free as people throw them away, and it's a nice easy fix.