AOC Envision 32 inch L32W761 no picture or sound

[Bilbo]

Re: AOC Envision 32 inch L32W761 no picture or sound

K, in diode mode r976 (power board installed) reads 1946 ohms, 1767 in 2k, spare board r976 flux some then reads 0 in both settings.

[budm]

Re: AOC Envision 32 inch L32W761 no picture or sound

Do you have soldering Iron? Unsolder one leg of the resistor so you can lift one leg of the resistor off the board, then take the resistance reading again on the two legs of the resistor using Ohm mode. You may have bad MOSFET.

[Bilbo]

Re: AOC Envision 32 inch L32W761 no picture or sound

Sorry, disregard double post

[Bilbo]

Re: AOC Envision 32 inch L32W761 no picture or sound

Yes I have an iron, I'll check both to compare, give me a few minutes and I'll get right back to you.

[budm]

Re: AOC Envision 32 inch L32W761 no picture or sound

BTW, do you have 24Vdc using the spare board?

[Bilbo]

Re: AOC Envision 32 inch L32W761 no picture or sound

Spare board has no 24 volts also. Desoldered r976 from both boards and they are both open. Guess I'll pick up a couple resistors and go from there. Thanks a lot for your time and help.

[budm]

Re: AOC Envision 32 inch L32W761 no picture or sound

More likely the MOSFET is shorted out, that is why the fusible resistor blown up. In this kind of case, the IC, the MOSFET, and the resistor should be replaced at the same time.

[Bilbo]

Re: AOC Envision 32 inch L32W761 no picture or sound

I'm not sure what you mean by MOSFET and which IC, (guess I need to look at the diagram for that side of the board to learn more) please let me know board location numbers and I'll get them on Order. Sorry kinda tired was a long day at work and getting late for me. Thanks again for all the help and you have a good one budm, night.

[Bilbo]

Re: AOC Envision 32 inch L32W761 no picture or sound

Disregard last post, I read back through post and found the component numbers. I'm researching parts now. Some are stated in other threads, Dynex DX-LCD32 Power Board, looks pretty close to the power board I'm working on. The Dynex is a -2 and mine in a -4.

Originally Posted by fleetwise
PlainBill is right. It is Digikey # 568-5344-1-ND for the TEA1532CT. I also found the mosfet shorted and 2 resisters burned open. I replaced the mosfet (STP10NK70FZP)at location Q902 with one rated for 800 volts. Digikey # . The resisters were at R933 and R976. I used 0.1 ohm 2 watt MO, Digikey# RSMF2JTR100CT-ND.

I checked with Digikey and all the have in stock is the MOSFET, still looking for the resistor and IC. I may have to order from eBay with shipping from China. Know where I may find some without buying a bulk package?

[budm]

Re: AOC Envision 32 inch L32W761 no picture or sound

You will need to check the resistance reading between the Source pin and the Drain pin of the MOSFET to see if it shows very low resistance reading, use Ohm mode not diode mode.

[Bilbo]

Re: AOC Envision 32 inch L32W761 no picture or sound

With q902 installed in boards I'm getting .4 ohm original board and .9 ohms on the spare from pin s to d. Or should I remove them from the board for check out? Info you I need to desolder r933 because they may also be bad on both boards.

[Bilbo]

Re: AOC Envision 32 inch L32W761 no picture or sound

R933s are fried on both boards, was hard to see due to heat shrink. Here's a picture of burnt r976 and r933.

[Bilbo]

Re: AOC Envision 32 inch L32W761 no picture or sound

Desoldered r970 (on both power boards) and both are reading open. I'm glad I waited to order parts, seems like both boards have same exact problem. I was hoping to at least steal parts from one the make the other functional. But not looking that way now.
By the way;
(Original board). (Spare board)
d903; reads 596 and open 592 and open
d907; 748 and open 751 and open
d917; 594 and open 595 and open
zd902; 925 and open. 921 and open
D920; 010 and 010. 010 and 010. Bad

Any suggestions of what I should check next?

[budm]

Re: AOC Envision 32 inch L32W761 no picture or sound

Q902 MOSFET should be removed and tested off the board so we will know for sure if it is shorted out or not. And if the S to D is shown as shorted, then you should order the IC at the same time because if the IC is also damaged (no way to tell for sure if the IC is 1005 good or bad) it will cause the damage to the the new MOSFET.

[Bilbo]

Re: AOC Envision 32 inch L32W761 no picture or sound

Ok, I'll remove q902 right now, so you mean, if low resistance it bad right?

[budm]

Re: AOC Envision 32 inch L32W761 no picture or sound

Yes, I suspect it will have very low resistance between S and D which will explain why the fusible resistor blew up.

[Bilbo]

Re: AOC Envision 32 inch L32W761 no picture or sound

Ok, I'll removed q902, it reads 0.5 between S and D, 21.2 between D and G, and 21.2 between S and G.
I'll order ic902, q902, r933, r970, r976, and d920 (which I guess is bad) for both boards, with some spares, hehe. Thanks again budm your have a great night. I'll let ya know when I get the parts in, take it easy.

[Bilbo]

Re: AOC Envision 32 inch L32W761 no picture or sound

Finally received the parts a few days ago. (By the way D920 checked good after removal from the board, was picking up readings from R958). Replaced R933, R976, Q902 and IC902 on original and spare power boards. With original board installed tv came right on and works fine. (I'm surprised someone isn't selling a repair kit for this boards with above parts) My friend says thanks budm.

The spare inverter, t-con and main board all checked good.

But when I installed the spare power board, tv came on and worked fine, then after a few minutes it fried (smoked) D901. This maybe due to; when I was checking power to C973 in previous steps above my test probe slipped and hit both + and -. (Dumb me, forgot to replace C973 and C919 before powering spare board up.

So my new question is, the only markings I can found on D901 is CH7h ML35, what kind of diode is this and where could I find a good part number? The one in parts list doesn't seem to cross. Is it possible that some other components fried with it? (I have two new 100uf 450v caps for C973 and C919. It would still be nice to get the spare power board fixed/working also, never know when someone may need it.

[Bgentle]

Re: AOC Envision 32 inch L32W761 no picture or sound

I am very confused. I have an Envision L32W761 that periodically goes black. I still have sound and the flashlight test show a faint image. I have been reading this thread and realize that it is several years old so I don't know if I will get a response or not. My set only has three boards, the TCON, Power supply and the video board. I am trying to find the inverter components to no avail. I am afraid they are part of the screen. Can anyone shed some light on this?

[dick_barton]

Re: AOC Envision 32 inch L32W761 no picture or sound

There should also be an inverter board as shown in this link. The one with all the small transformers on.
http://www.edaboard.com/thread180029.html