Vizio VW37L HDTV20A Power supply No Standby Voltage

[budm]

Re: Vizio VW37L HDTV20A Power supply No Standby Voltage

So with the bridge rectifier removed, the short is no loger there then on the output side of the rectifier.
And if you measure the two pad where the rectifier AC (~) INPUTS are, do you get short circuit?

[Worminizer]

Re: Vizio VW37L HDTV20A Power supply No Standby Voltage

The short goes away on the non feed side after the bridge rectifier is pulled. It remains, until the inductor is pulled. After that its all ok, so there are at least two troubles in components.

[budm]

Re: Vizio VW37L HDTV20A Power supply No Standby Voltage

Burnt out line filter is really rare, it must have had a lot of current flowing through them, I would expect the fuse to blow before they shorted out like that, the filter can be removed and bypassed for testing other function of the board.

[Worminizer]

Re: Vizio VW37L HDTV20A Power supply No Standby Voltage

oh, good, I'll get a new rectifier and see if I can get it back to life then. I have a few power supplies laying around. I will see if there are any rectifiers I can scavenge.

[Worminizer]

Re: Vizio VW37L HDTV20A Power supply No Standby Voltage

by the way, I took a good portion of the shock myself. I'm pretty used to getting hit at work by leaning my arm against an array of T-1's, Ringing generators, and power feeds, Stupid I know, but its a good reminder to be careful, because there are more hazardous voltages than just 120vac in a tv set.

[budm]

Re: Vizio VW37L HDTV20A Power supply No Standby Voltage

I would plug the TV into a GFI outlets for safety and also use an Isolation transformer as well.
http://s807.photobucket.com/albums/y...t=DSC00073.jpg

[Worminizer]

Re: Vizio VW37L HDTV20A Power supply No Standby Voltage

I will be doing just that.

[Worminizer]

Re: Vizio VW37L HDTV20A Power supply No Standby Voltage

Could you help me distinguish which bridge rectifier I should order from digikey? I have looked, and there are over 2000 to choose from. I am just not that familiar with the devices to know the difference. Here is the datasheet, it is an 8k.
http://pdf1.alldatasheet.com/datashe.../US8KB80R.html

[budm]

Re: Vizio VW37L HDTV20A Power supply No Standby Voltage

It is 800V 8AMPS D6K package.
You can get it from here:
http://www.bdent.com/US8KB80R-7000-p/us8kb80r-7000.htm
I did not find the same D6K package style at DIGIKEY.

Or the higher current rating one with the same case size:
http://www.bdent.com/US15KB80R-7000-...kb80r-7000.htm

[Worminizer]

Re: Vizio VW37L HDTV20A Power supply No Standby Voltage

thanks bud

[Worminizer]

Re: Vizio VW37L HDTV20A Power supply No Standby Voltage

Ok, I got my bridge rectifiers in, I threw one in, and remade my own inductor. I re-wrapped the magnet with new wire, and actually made it new again. Everything is back to where I was before I oopsed. I also changed out both of those capacitors with new low esr ones, though neither one tested faulty with either a capacitance tester on the fluke, or the esr meter. I still get 0v on the 5v rail. What would I check/replace next? Should I order a new controller IC?

[Worminizer]

Re: Vizio VW37L HDTV20A Power supply No Standby Voltage

Ok, I reread the whole thread, since its been a while, and I looked at what retiredcaps had said,
2) A fluctuating voltage suggests one of the following

a) the startup cap, c213, is bad (the small ones rarely bloat)
b) the SMPS IC is bad
c) there is something shorted on the secondary output side (like a diode)

3) The SMPS IC needs stable DC voltage in order to work properly.

I began looking at the diodes on the board, and found one that isn't shorted, but it's wide open, and visibly has a chunk blown out of it. I will attach a photo. I can still see from what is left that it is an A2 in location D207. I will try to salvage one from something else and see if it fixes my problem. I'm not sure what the value is though...

[retiredcaps]

Re: Vizio VW37L HDTV20A Power supply No Standby Voltage

I can still see from what is left that it is an A2 in location D207.

I don't have any experience in deciphering these smd 2 letter codes, but this

http://www.s-manuals.com/smd/a2

leads to



which leads to my guess as it being UDZS 5.1B A2.