westinghouse vr3215

[johnz]

westinghouse vr3215 has 5v but no 12v or 24v?? Help what to check next here are some pics..I have replaced all the caps.

[johnz]

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

[budm]

Re: westinghouse vr3215

The problem is in the power supply since it is getting the correct signal feeding it.
What voltage do you have on the two legs of the large filter cap (you will be working in the primary hot side, so be real careful not to touch anything), it should have about 380~400VDC on it.

[johnz]

Re: westinghouse vr3215

It jumps between 393 to 397..

[budm]

Re: westinghouse vr3215

Good, the PFC is OK, if the 390v is not present, the 12v/24v circuit will not run. So now we need to check the 12v/24v SMP section. I will have to trace out the copper traces on the bottom side of the board to see how they are connected, it will be really time consuming task. Did you look and find out how much the new board will be yet?

[johnz]

Re: westinghouse vr3215

yes .....59.99+tax ..http://www.shopjimmy.com/westinghous...upply-unit.htm ...thanks for helping me out here..!

[budm]

Re: westinghouse vr3215

That will be worth it for quick fix.

[johnz]

Re: westinghouse vr3215

just wanted to know if it was the power board..thanks for your help.

[shwsrvcs]

Re: westinghouse vr3215

boo... I got my hopes up as I am trying to figure this out right now.. all caps look good, all voltages, the same... could anybody continue on with this diagnosis?

[tom66]

Re: westinghouse vr3215

Check the diodes on the output side are not shorted.

[shwsrvcs]

Re: westinghouse vr3215

Check the diodes on the output side are not shorted.

thanks, I will do that!

[lookimback]

Re: westinghouse vr3215

I'm working on one of these right now. I can't actually see anything wrong. I tested all the caps but decided I don't trust the tester because brand new Panasonics that I tested came up about 100uf off. As for voltages, I have about 169v on the bridge rectifier and the same across the pfc. Output voltages are below. I think if I had a better multi meter and capacitor tester I could figure this out.

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

NO 24v all 0

Edit: I also tried freeze spray but nothing happened.

[budm]

Re: westinghouse vr3215

@look, you are not getting STB (PS_ON) signal form the main board to turn on this power supply. The voltage reading is done after the power switch is activated?

[lookimback]

Re: westinghouse vr3215

I did the testing with the board out and disconnected. So, I'll reconnect it and test again when I get home. Are there terminals I can jump to switch the STB on? Now you got me thinking it might not be the power supply. I'll retest when I get home and post the results. Thanks!


As for test equipment , I have a Radio Shack multimeter and its worthless for anything other than checking voltage. My capacitor tester came from Amazon and also is worthless. I ordered a Fluke 115 off eBay this morning.

[budm]

Re: westinghouse vr3215

Use 1K resistor between the STBY PIN and the +5stby pin.

[lookimback]

Re: westinghouse vr3215

OK thanks. I'll do that and post back. Might be a couple days because I'll have to order a 5k resistor. I'm ordering some other parts from Digikey anyway.

[lookimback]

Re: westinghouse vr3215

OK I put the board back in and reconnected everything. I have the correct voltages on all the terminals. I guess that brings it to either the inverter board or a bad ccfl. I took the screen out and looked at the ccfls. Here is a pic of them when I power on. They don't fully light and go out in about 1 second. I also hear a slight humming sound.

[budm]

Re: westinghouse vr3215

OK, so now you do get the 24vdc to feed the inverter board? if that is the case, you will need to see if the inverter board is OK, you can check all the fuses, the resistance readings of the high voltage side of the inverter transformers, etc.

[lookimback]

Re: westinghouse vr3215

On the inverter board I have 2 wires that come from the main board. They are BK and DM. BK voltage is 2.9v and DM is 1.2v. I don't know what is normal.

OK the resistances on the high voltage side are, if I did this correctly (I tested via the solder points which lead to the ccfl connectors), 1.308k, 1.303k, 1.282k, 1.280k. As for fuses, I don't see anything I recognize as a fuse. I'm new to SMD components so if some of them are fuse I'll need you to describe them. Thanks.

[budm]

Re: westinghouse vr3215

"BK voltage is 2.9v and DM is 1.2v."
BK is more likely to be Backlights ON signal from the main board.
DM is the Backlights Dimming control voltage from the main board, 5V = Max lamps brightness, 0V = dimmed.
So it looks like the Main board is sending out the correct signals to the Inverter board, but the Inverter board will need 24Vdc from the power supply board to run. So do you have 24VDC? Pictures of the inverter board needed before I will go further.