Please help I'm loosing my mind 65" tv

[Danvagos]

Re: Please help I'm loosing my mind 65" tv


I'm sorry for all the post I just would really like to narrow down what board is the problem if I tested here at the spot which is right off of where the power comes in this board with the brown spot underneath comes up at .250 after giving the meter a little bit of time to equal out the other two boards at the same spot are at 17.20 and 12.50 now I'm really confused

[mmartell]

Re: Please help I'm loosing my mind 65" tv

I have not read this thread but I do have the boards from this set if you need me to take a measurement. The tv they came from had 2 seconds to black and a cracked screen.

[CapLeaker]

Re: Please help I'm loosing my mind 65" tv

I'm sorry for all the post I just would really like to narrow down what board is the problem if I tested here at the spot which is right off of where the power comes in this board with the brown spot underneath comes up at .250 after giving the meter a little bit of time to equal out the other two boards at the same spot are at 17.20 and 12.50 now I'm really confused

Whaaat? We just found the problem transformer. What are you trying to say here? Now I am confused.

[dick_barton]

Re: Please help I'm loosing my mind 65" tv

the transformer measuring 7.08 is the problem

+ I would also tend to agree with CapLeaker.
There are signs of overheating due to increased current on that board and one of the transformers measures out of tolerance to the others on the same board.

[Danvagos]

Re: Please help I'm loosing my mind 65" tv

Sorry I was still confused lol so that little bit of difference is the problem ? And thank you all for your help this sight is great and now my friend has a 55 in Samsung doing the same thing

[CapLeaker]

Re: Please help I'm loosing my mind 65" tv

Yes, that little bit of difference makes exact this problem. As I already mentioned before looking at the secondary of each inverter transformer, you have to find a base line what most of them transformers measure. Off that base line (your case 7.33) you measured one that had 7.08. Inverter transformers are bad when they are about 3% off.
So you calculate:
7.33 : 100 = 0.0733
0.073 x 3 = 0.2199
7.33 - 0.2199 = 7.1101

You measured 7.08, so that is more than 3%.
What happens is that exact that transformer is drawing more current than the others. It draws more current, it also will get hotter than the others. The inverter notices that and shuts off.

So you need to get a spare transformer or a replacement inverter board.

[Danvagos]

Re: Please help I'm loosing my mind 65" tv

Thanks so much I have the #1 board and a spair #2 board coming

[CapLeaker]

Re: Please help I'm loosing my mind 65" tv

keep us updated!

[Danvagos]

Re: Please help I'm loosing my mind 65" tv

I'm ready to give up!! Got two boards in one # 1 and a # 2 and still nothing. Any more ideas it still turns on then shuts off

[Danvagos]

Re: Please help I'm loosing my mind ( UPDATED !!! )

I just don't know where to go now !

[CapLeaker]

Re: Please help I'm loosing my mind 65" tv

Did you check the secondary's of the transformers on the boards you bought? I can't remember, but what the board number that we diagnosed with the bad inverter transformer? #2?

[CapLeaker]

Re: Please help I'm loosing my mind 65" tv

err it was the #1 board (had to reread this thread).
Logic tells me, that the inverter detects some sort of fault after it tries to fire up the backlights. So the control IC (BD9777) is o.k.

You can go over the inverter boards again and make sure the inverter transformer secondary's are good. After that, I would resolder each transformer and I also would resolder those two 5KV capacitors on each transformer output to GND.

I think there is another issue on one of the other boards or there is a CCFL going bad.

Another problem is that I can't find a datasheet for the BD9777 to see the pin out in order to remove the protection circuit.

[Hombre]

Re: Please help I'm loosing my mind 65" tv

...

Another problem is that I can't find a datasheet for the BD9777 to see the pin out in order to remove the protection circuit.

It's not datasheet but maybe it can help

https://www.badcaps.net/forum/showthread.php?t=33129

[CapLeaker]

Re: Please help I'm loosing my mind 65" tv

Nice find Hombre! Cording to this jump pin 14 of this consol IC to GND. TUrn it on an see what happens!

[Danvagos]

Re: Please help I'm loosing my mind 65" tv

FOUND IT !! it was

[Danvagos]

Re: Please help I'm loosing my mind 65" tv

FOUND IT !! it was one of the new used boards I guess one of the transforms was bad. I put one of the old boards back in and bammmmmm it's works. Thank you all

[CapLeaker]

Re: Please help I'm loosing my mind 65" tv

sweet! Nice repair! keep the other boards for spare transformers!

[mmartell]

Re: Please help I'm loosing my mind 65" tv

Wait. How does putting the old board back in fix the original problem ?

[dick_barton]

Re: Please help I'm loosing my mind 65" tv

I think two boards were ordered and replaced but only one of the original boards looked as though it had a bad transformer. Danvagos can put me straight on this.

[Danvagos]

Re: Please help I'm loosing my mind 65" tv

Ok I found the bad board with the burn mark so I ordered a replacement but got a #2 by mistake so I then ordered a #1 so when the both cam in I just installed both because the looked better then my boards lol well I guess I was wrong so after installing and it still not working I retested the two boards and found one bad transformer was bad. The place I ordered them from is sending me a spare. I now have a spare main a t-con and two bad and one good transformer boards lol