TV Power Supply Repair (Vestel 17IPS20)

[smilgy]

Hi,

I was wondering if you perhaps could help me troubleshoot a TV power supply that has failed.

In my process of troubleshooting, I have found the main fuse, bridge rectifier diodes (D112, D113, D114 and D115 on the attached schematic), as well as D101, D512 and D513 in S/C. I replaced the fuse, and the mentioned diodes, however all of the above failed again, as there is probably still another short somewhere? However, I am unable to find it (relatively inexperienced in this subject). Any thoughts what I should be checking next?

Thanks,
David

[inse]

This is the nastiest schematic I've seen for as long as I can remember.
It is not a document to support repair, it's an obstacle!
A dead Q301 might kill D512/513.
Only D101 broken, but not 102 and 506 (who made those references???)
Are D104 and the bridge rectifier diodes (D112, D113, D114 and D115) in parallel, or am I too stupid to read this schematic?

[smilgy]

It took a bit of effort to remove q301, but I did. Would I be right in saying that it is dead judging by the tester?

[wasedadoc]

It took a bit of effort to remove q301, but I did. Would I be right in saying that it is dead judging by the tester?

Yes.

[smilgy]

Replaced the mosfet with a close similar, and TV powers on! Time to get the correct replacement.

[inse]

Double thumbs up 

[FIXITNOW2003]

Training book for psu if anyone else drops on to this page ,it may help

[smilgy]

Training book for psu if anyone else drops on to this page ,it may help

Thanks, I'm sure this will help someone. I had initially thought Q301 had failed, but was not 100% sure with the component in circuit. I had forgotten I had the component tester as pictured, and once removed and tested, it seemed obvious, especially the S/C path taken.

I'm by no means an expert at repair, so was fun to fix this, even if with the help of others!