Polaroid FLM-3201 Power Supply Issue

[aaronwt6]

Got a Polaroid TV with a PS issue here. Main fuse right by the AC input was blown. Figured something caused it but I gave it a shot. Blew instantly again as good as I put power back to it. Any advice on where to start?

Repairing this for someone and the board is waaaaay to expensive. Cheapest I see is $75.

Thanks,

Aaron

[tom66]

Re: Polaroid FLM-3201 Power Supply Issue

It's probably not the main fault, but there are a few bad capacitors on the output too.
Is this a KAS200 supply?

[aaronwt6]

Re: Polaroid FLM-3201 Power Supply Issue

Yes, I see the caps and realize they need replacing but was trying to figure out what's blowing the fuse first.

[aaronwt6]

Re: Polaroid FLM-3201 Power Supply Issue

If I can get it to power up then I'll move on to the caps. Looks like at least 3 that need to be done.

[tom66]

Re: Polaroid FLM-3201 Power Supply Issue

KAS200?


You can check the FETs and bridge for shorts.

[capkid]

Re: Polaroid FLM-3201 Power Supply Issue

I'd replace all the caps on the output side, since they're most likely terrible low-voltage HEC caps; HECs fail sometimes without visible signs of failure. An ESR meter would come in handy. I'm not sure that will keep the fuse from blowing, though (doubt it).

[aaronwt6]

Re: Polaroid FLM-3201 Power Supply Issue

KAS200?


You can check the FETs and bridge for shorts.

Yes sir. KAS200

[aaronwt6]

Re: Polaroid FLM-3201 Power Supply Issue

I'm probably going to have to mess with this after my vacation. Leaving tomorrow. I'm going to get in trouble with the wife if I don't help pack. My meter is showing shorts all over the place and I haven't done enough reading on the testing to jump into it.

Will certainly do the caps to if I can get it going.

And that's for the schematic Tom. Really appreciate that.

[aaronwt6]

Re: Polaroid FLM-3201 Power Supply Issue

Found a supply for like $45 shipped but it's in the UK.

http://www.ebay.com/itm/32-LCD-TV-PA...item461150ed25

[tom66]

Re: Polaroid FLM-3201 Power Supply Issue

I've got a -very- broken PSU like this that's had a lot of work done on it by someone else, I can compare some measurements if necessary but I have also provided a schematic so it's just a matter of isolating the fault.

[aaronwt6]

Re: Polaroid FLM-3201 Power Supply Issue

I'm going to work on it when we get back from vacation next week. Just to rushed to sit down with it this evening. I'd certainly rather fix it.

[aaronwt6]

Re: Polaroid FLM-3201 Power Supply Issue

On the FETs Tom. I believe these are just Q905, Q906, and Q907? One is a heck of a lot bigger. Can't read numbers on them without removing.

[tom66]

Re: Polaroid FLM-3201 Power Supply Issue

Part #s in schematic, use those if you have problems reading the numbers.

[aaronwt6]

Re: Polaroid FLM-3201 Power Supply Issue

My meter shows short between all 3 legs on Q905. Looks like I have to pull D902 also to remove the heat sink that it's on.

[aaronwt6]

Re: Polaroid FLM-3201 Power Supply Issue

I'm pretty sure that one is bad. 600v 20a. I'm also pretty sure I have one in another supply that I could steal. An ST micro w20nm60.

Not certain on that though.

[aaronwt6]

Re: Polaroid FLM-3201 Power Supply Issue

Pulled that one. Definitely shorted. I'll order and have it here when I get home next week. Spec not quite the same on the one in the other board.

[aaronwt6]

Re: Polaroid FLM-3201 Power Supply Issue

Q905 was the culprit. TV is up and running and you're a life saver as always Tom. I'm learning here......slowly.