westinghouse vr3215

[budm]

Re: westinghouse vr3215

Hi Budm. Do you have any experience about buying stuff from this website? (iccfl.com) Can't find this IC anywhere else and I'm curious of finding the fix.

Sorry, no.

[Louis82]

Re: westinghouse vr3215

Hi Budm. Do you have any experience about buying stuff from this website? (iccfl.com) Can't find this IC anywhere else and I'm curious of finding the fix.

[budm]

Re: westinghouse vr3215

I see people selling them but I cannot find the spec sheet.
http://www.iccfl.com/product_info.php?products_id=23550

Resistor is OK.

[Louis82]

Re: westinghouse vr3215

IC U301 P/n : 63b26
R309 (on the board) reads <1 Ohm

[budm]

Re: westinghouse vr3215

OK, the 12V and the 24V are generated by the same power transformer T1 which is driven by the power MASFET Q103. Q103 is driven by the SMPS IC U301.
The 12V/24V power supply section is turned on by the PS_ON (STBY) signal and we know that the signal is OK otherwise you will not have the PFC Boosted Voltage.
You need to find out the P/N of the SMPS IC U301 to see if it is geTting the VCC to run the IC.
Also check the Source resistor that is connected to the Source pin of the Q103, it should be < 1 Ohms.

[Louis82]

Re: westinghouse vr3215

Better pics from Shopjimmy.

[Louis82]

Re: westinghouse vr3215

Hope these pictures look better.
Thank you

[budm]

Re: westinghouse vr3215

Hello,

I have same issue. No 12v, 24v. Big cap reads 391v. Using 1k resistor between STB and 5vSB.

I have checked diodes D500 and D501 and there is no input voltage. Ordering a board is an option but I'm very curious on finding what's wrong with this power board.

I will appreaciate any help. Pics are attached.

The pictures are cutout and do not show the whole board.

[Louis82]

Re: westinghouse vr3215

Hello,

I have same issue. No 12v, 24v. Big cap reads 391v. Using 1k resistor between STB and 5vSB.

I have checked diodes D500 and D501 and there is no input voltage. Ordering a board is an option but I'm very curious on finding what's wrong with this power board.

I will appreaciate any help. Pics are attached.

[budm]

Re: westinghouse vr3215

Good clear straight shot pictures of your board top and bottom side will help.

[Dr. Bogger]

Re: westinghouse vr3215

UPDATE:

The transformer that supplies both 12v and 24v has no output, and also no input.

The other transformer has a 390v Input, so I'm assuming this one should be getting the same???

Any help would be great!

[Dr. Bogger]

Re: westinghouse vr3215

ok here are somre readings i got

+12v = 0
+12v = 0
GND
GND
GND
+5v =5.2
+5v =5.2
+5VSB =5.2
STB =3.5
+5V =5.2
+5v = 5.2
GND
GND

NO 24v all 0

I am having the same voltages as above.
I seem to have lost 12v and 24v supply.

I want to see if I can figure out the issue before I spend the money on a new power supply.

I have tested the voltage on the large cap, and I get about 393v.

I have tested all the diodes, and all seems good, except one is acting like a zener diode, and I'm not sure if it is a zener diode or not. Location: JM8

I haven't tested any of the caps yet, but I have a feeling it's not a cap issue. Plus my ESR meter is a cheapo.

What do you suggest I check next?

[lookimback]

Re: westinghouse vr3215

Yes, I'm going to remember this one myself as well. It never occurred to me that someone else might have tried to fix it themselves and made it worse. The electrolytic did test bad so maybe that was the original problem. Thanks for all the help with this one. Honestly, if not for your help I would probably still be messing with the power board. I learned a lot from this one.

[budm]

Re: westinghouse vr3215

Thanks for feedback. Notes to myself: suggest to have ALL the connectors pins checked out also.

[lookimback]

Re: westinghouse vr3215

I got it. You will never believe what it was. There was a bent over terminal in one of the lamp connectors on the inverter board. I had swapped 19 SMD caps (most 1 at a time, then retesting), 1 switching diode and the PWM IC before finally getting it to stay on for a few seconds. During that few seconds it started to sizzle. I didn't realize right away what it was. I removed 4 more caps and tried them in the good board. These were the final 4 that were part of the lamp circuit. It was while I was soldering them in that I thought to check the terminals in all the connectors. The crazy thing is that the TV could never have worked with that terminal bent. I think the person I bought it from must have tried to fix it himself and bent the terminal. The only thing I've replaced on the TV is the electrolytic cap on the top of the board. I first put a temporary cap in just to see if it would work. Then last night I replaced that with a Panasonic FC. I just can't believe how simple it was.

This confirms what I had concluded from testing. It was the lamp fail safe protection causing the shutdown.

[lookimback]

Re: westinghouse vr3215

New board came today. Works great. I'm still working on the old one. I've been swapping components between the boards. The PWM IC is good. I've swapped out the PWM IC, about 6 caps and one switching diode(was giving me different values than the one in the good board). All are part of the lamp fail safe circuit which connect to pin one (CS). I've got about 10 more caps in the circuit. Also compared values of every resistor, diode, transistor, etc. Values were all almost exactly the same as good board. It pretty much has to be a bad cap. I didn't compare values on the HV transformers yet. I'll do that first tomorrow. Right now I'm going to call it a night.

Edit: My new Fluke multimeter also came today. It puts the Radio Shack one I've been using to shame.

[lookimback]

Re: westinghouse vr3215

ok, im going to try that

[budm]

Re: westinghouse vr3215

If the IC is cheap, then you can try replacing the IC. BTW, the application notes circuit just about matches my drawing as far as the MOSFETs and the transformers are connected. Pin 3 is the timer, if you tie that pin 3 to ground, it will keep on trying to fire the lamps up.
I have a feeling the circuit they using is copied from the application notes.

[lookimback]

Re: westinghouse vr3215

I ordered it already. I appreciate the help with this too. I'm going to compare values when the new board comes but I think I have it almost figured out. The data sheet was the key.

[budm]

Re: westinghouse vr3215

It looks like you are going to have to spend the money on the new board at this point.