Hanns G HW191DP inverter board, in need of Help.

[ScientistJoe]

Hello,

This is my first time posting here, I found this site very useful in repairing the inverter board in my Westinghouse 1975NW. I now have a similar problem with a Hanns G HW191DP. I haven't been able to find much information on it and i was hopeing someone here, with a little more experience, might be able to shed a little light on my situation.

I will start by replacing the electrolytics, but I was wondering if any other components would need replacing as did in the Westinghouse model (a smd fuse, and 2 mosfets.) I'm sure I can test the 3 red fuses myself but I'm not sure about the mosfets or other larger smd compontents.

I took some pictures of the board, The burst caps are marked with an x, all electrolytics have values labeled in red, the fuses I found are circled in orange, semiconductors labeled in yellow.

What I would like to know is how likely is it that one of the mosfets or smd components needs replacing, I caught this problem early when it first began failing; and lets say I will replace the 470uF caps and 1000uf caps, am i correct in assuming the 100uF 400v is fine, as it has not burst, or should i replace it aswell?



All the fuse locations I could find:

F901 - missing
F901A - missing
F801 - 2A
F802 - 2A
F803 - 2A



Any help anyone can give me will be appreciated.

Cheers!

[ScientistJoe]

Re: Hanns G HW191DP inverter board, in need of Help.

So I've found it to be a TJ777 VP-775 Power Supply Board. If that help.

[retiredcaps]

Re: Hanns G HW191DP inverter board, in need of Help.

I will start by replacing the electrolytics,

Replace them ALL. 7 out 10 have visibly failed not counting the big one.

What I would like to know is how likely is it that one of the mosfets or smd components needs replacing,

You can take a look at this

https://www.badcaps.net/forum/showthread.php?t=10419

It has instructions on how to test a fuse, transistor, and other components.

am i correct in assuming the 100uF 400v is fine, as it has not burst, or should i replace it aswell?

The big cap rarely, but not never, fails. It is optional, but seeing out 7 out of 10 have failed, you might as well recap the big one.

PS. Please don't post images inline. They slow down the loading of pages. Follow this instructions.

https://www.badcaps.net/forum/showthread.php?t=1868

[ScientistJoe]

Re: Hanns G HW191DP inverter board, in need of Help.

I apologize for the inline pictures I didn't know how to put them in as an attachment and I couldn't edit the post to change them to URL.

Thank you for you good advice I'll check those links out.

[jetadm123]

Re: Hanns G HW191DP inverter board, in need of Help.

I agree that replacing the caps is a step in the right direction, but you never did describe the problem with your monitor. Replacing fuses and mosfets at this point without checking them first would be a waste of money.

[ScientistJoe]

Re: Hanns G HW191DP inverter board, in need of Help.

Forgive me the problem presented like a previous monitor I had (that required caps and mosfets, apparently it was a common problem and was able to find a kit with all the needed parts.) At first it was slow to respond after hibernating then, it would come on for a few seconds then go dark, image viewable with a flashlight, indicating inverter of back light. The monitor would finally come on after a few power cycles. at this point I stopped using it and began disassembling the monitor.

I've replaced many caps mostly working with tube amps, I'm afraid I never learned much about FETs and since there is no clear cut replace this to fix that common problem I was hoping for some in sight on how to diagnose the inverter board.

I've since tested all the fuses in place and they seem fine. I will replace caps sometime this week when I get the parts and go from there.