Vizio VM60P HDTV10A No signs of life except speaker pop when unplugged

[vinceroger69]

Re: Vizio VM60P HDTV10A No signs of life except speaker pop when unplugged

in post 65 you mentioned mosfet testing so i sent you that link but when i just re read the whole posts and googled the number it says k2865 is a transistor not sure why it passed the mosfet test though. whats the part number on the long ic thats blown as these power supplies seem very expesive.
have you tested the k2865 out of circuit also has your new resistor now gone open circuit as well?

[heavymachines]

Re: Vizio VM60P HDTV10A No signs of life except speaker pop when unplugged

weird but new resister still test 10 ohms, my gut tells me there is a prob elsewhere, the number on long ic is kia339p the longer ic is l4981a. yeah there not cheap found one for 60 somthin hope he takes the offer.

[heavymachines]

Re: Vizio VM60P HDTV10A No signs of life except speaker pop when unplugged

will have to retest the transistor however when it fried it took a few things with it a resistor for sure and not sure bout those ic's and the diode's are suspect as well it smells fried sky high.

[vinceroger69]

Re: Vizio VM60P HDTV10A No signs of life except speaker pop when unplugged

the kia339p is quiet cheap http://www.ebay.co.uk/itm/KIA339P-Ma...item19d16f259b
but the problem is what else has gone wrong

[cheebster]

Re: Vizio VM60P HDTV10A No signs of life except speaker pop when unplugged

hi there. just a little input on this..

here's the pdf for the datasheet of this ic :

https://cdn.badcaps-static.com/pdfs/...3af77752b5.pdf

and here's a replacement that seems to be fine in stock at digikey.. cross refs as a

http://www.digikey.com/scripts/dksea...LM339N&stock=1

lm339n or others.. see link

http://www.allxref.com/kec/kia339p.htm

have a nice one

[tom66]

Re: Vizio VM60P HDTV10A No signs of life except speaker pop when unplugged

LM339 is nearly indestructible as far as ICs go. It is just an analog comparator.

[heavymachines]

Re: Vizio VM60P HDTV10A No signs of life except speaker pop when unplugged

well i darn thing went to pcb heaven the resistor was definitely part of the prob but there was more bad components in store for me and it went poof could be cause of that transistor which i thought was a mosfet, i gave the part number to verify and well it was verified too late as a transistor. well the internet sucks cause i put that part number in and the doofy thing said mosfet, later, oleboy said its a transistor LOL. blah now there are several fried components its like bah just replace the pos, and go from there, now what i am afraid to death of is there something on the other supply that is bad that can cause a repeat of this frying venture? i have no real way of telling and when it comes down to components well i am a greenhorn, rookie, however you like to word it, and yes i have fixed displays but that's because they already figured it out for me or because i just replaced what i knew was the offending board. only one time did i manage to figure out on my own was a pos hanns g 22" and i figured out it had bad bulbs did that with no help at all but that's one time. this thing has 3 power boards and i know for sure the lower one is shot and stinks now lol, not fantastic on identifying components nor reading schematics again a greenhorn LOL. now caps and some resistors i can test fine however resistor with color bands, transistor, mosfets ,hybrid i am lost, however i can follow instruction with some good illustration,but if i throw a part number out and call it a mosfet PLEASE correct me before i misdiagnose the darn thing lol ,well resistor fixed part of it but now there is a bigger prob then i started with shoot.

[tom66]

Re: Vizio VM60P HDTV10A No signs of life except speaker pop when unplugged

Hmm, I am pretty sure your line filter is OK, and it cannot damage the other two.

Your second lower board is only converting the 115V/230V rectified DC into approx 400V for the rest of the TV. A failure here would damage the lower board, but would be very unlikely to take out the top board; it'd blow the fuse first.

It's only really when you get to plasma sustains and buffers that one board can damage others.

[heavymachines]

Re: Vizio VM60P HDTV10A No signs of life except speaker pop when unplugged

so you don't think there is anything in the upper power board that can damage the lower power board? where it fried is right by that plug coming from the upper power board.

[tom66]

Re: Vizio VM60P HDTV10A No signs of life except speaker pop when unplugged

I think at worst it would blow the fuse. You should be able to check the lower board without the upper board connected; the TV should stay in standby, and pressing the power button (might) make the relays click. That's as far as it would go. I say it might click the relays because they could be controlled from the bigger board.

[heavymachines]

Re: Vizio VM60P HDTV10A No signs of life except speaker pop when unplugged

well the power button is connected directly to the mainboard, when i connected it after putting in that resistor in i only hooked up those three power boards and left everything else disconnected and was about to test for standby voltages and before that could happen there was a flash and smoke within 10 seconds after connecting power. kinda glad i did it that way cause it could have taken more with it. only way that power button gonna work if i connect the mainboard, but i want to check everything before i do that to prevent what happened today it going up in smoke. in theory there should be standby voltage present for the mainboard to tell it to fully power on. look at that manual in the beginning of the thread there it will tell you the block diagram on page 6-1. take a look at it, it does not show every connection but it gives you a good idea on my layout.

[tom66]

Re: Vizio VM60P HDTV10A No signs of life except speaker pop when unplugged

My instructions only apply when the lower board is functional.

[heavymachines]

Re: Vizio VM60P HDTV10A No signs of life except speaker pop when unplugged

there has to be a way to test the upper board for shorts so i don't cook the new board when i put it in cause i doubt the guy is gonna refund me for a fried power board, but yeah this time i will test with just the line filter and the lower, and be scared as hell to connect the upper power board.

[tom66]

Re: Vizio VM60P HDTV10A No signs of life except speaker pop when unplugged

You can check the MOSFETs on it all for short circuits. You can simply test from source to drain, that is adequate for 99% of all MOSFETs.

[heavymachines]

Re: Vizio VM60P HDTV10A No signs of life except speaker pop when unplugged

also looking at this thing both mainboard and upper power board must be connected in order to get relay clicks cause #1 power button is directly connected to the mainboard, #2 there is a 2 er 3 small wire plug that runs from the upper power board to the filterboard right next to the relays, #3 the heavy wire plugs run from the filter board to the lower then from lower to upper.

[heavymachines]

Re: Vizio VM60P HDTV10A No signs of life except speaker pop when unplugged

then there is a bunch of small wire plugs conjoining the lower and upper in unison.

[tom66]

Re: Vizio VM60P HDTV10A No signs of life except speaker pop when unplugged

In which case you should still get standby power even if it won't go further than that. It could possibly be an idea to test with a new lower board, and same upper board, but without main power connector plugged into the upper board.

That way you'd still get relay clicks, but there's much more limited potential for damage as the rest is low voltage, low current.

[heavymachines]

Re: Vizio VM60P HDTV10A No signs of life except speaker pop when unplugged

perhaps i drew this out to give u a good idea how i think it works please correct me, and yes i think that may be a good idea.

[tom66]

Re: Vizio VM60P HDTV10A No signs of life except speaker pop when unplugged

I think you've got it nailed. The red/blue connector going from the small board to the larger one (not the line filter) should be OK to disconnect and try the TV without temporarily when the lower board is replaced/repaired.

[heavymachines]

Re: Vizio VM60P HDTV10A No signs of life except speaker pop when unplugged

so just leave the high voltage disconnected from lower to upper and the low voltage connected, that may work, just leave the one high voltage from the filter to the lower connected.