Samsung LE37A336 TCON fuse keeps blowing

[Jooo]

I got this Samsung LCD TV in for repair. It turns on, plays the startup melody and backlights turn on but the screen stays black.
I opened it up and found a open 3A fuse on TCON board so I replaced it, but this didn't fix the problem.
The newly replaced fuse had blown again. Thinking that the new fuse was already broken I replaced the TCON fuse again and this time tested it before putting the board back to tv. This still didn't fix the problem, so I tested the fuse and it had blown again.
So something is causing the TCON fuse to blow, what could it be?
Tcon model no. is T370XW02 or 37T03-C01

[tom66]

Re: Samsung LE37A336 TCON fuse keeps blowing

Does the T-con even work briefly or is it blowing fuses immediately?

[Jooo]

Re: Samsung LE37A336 TCON fuse keeps blowing

Does the T-con even work briefly or is it blowing fuses immediately?

The fuses blow immediately. Nothing comes to screen at all.

[tom66]

Re: Samsung LE37A336 TCON fuse keeps blowing

OK, try replacing the fuse but this time, disconnect the ribbons going to the top of the LCD panel, does the fuse still blow?

[jbfr_54]

Re: Samsung LE37A336 TCON fuse keeps blowing

If the fuse still blows when the panel ribbons are disconnected, try to locate any shorted SMD caps on the T-Con board. There are usually 6 or more caps wired just after the fuse, decoupling the panel power coming from the main board.
It happened to me several times that one of these caps is bad, shorting the 5 or 12 volts panel voltage. Replacing the bad ones with equivalent sized smd caps taken on another board is OK as they are not value sensitive and low voltage operating.

[tom66]

Re: Samsung LE37A336 TCON fuse keeps blowing

To build on jbfr's answer, I've had a shorted ceramic capacitor on the panel ribbon board, hidden under the LCD frame.
Typically they'll short the AVDD voltage, which is about 15V. This voltage can be hidden behind a diode drop, so ordinary ohms/continuity testing will not pick it up.

[MajesticMike]

Re: Samsung LE37A336 TCON fuse keeps blowing

and what should you do if the fuse doesn't blow when you unplug the ribbon cables?

thats where i'm at with the same issue.

[tom66]

Re: Samsung LE37A336 TCON fuse keeps blowing

The LCD panel might be bad or it could just be a capacitor shorted out, it can be hard to find.

[Bobo360]

Re: Samsung LE37A336 TCON fuse keeps blowing

Hi everyone, I also have the same problem described in the first post. Is the T-com card the one located high above the PSU?

Thank you

[diif]

Re: Samsung LE37A336 TCON fuse keeps blowing

Hi everyone, I also have the same problem described in the first post. Is the T-com card the one located high above the PSU?

Thank you

The small card in the middle at the top, possibly under a metal cover.
There will be a wide flat cable going from the mainboard to it.

[Bobo360]

Re: Samsung LE37A336 TCON fuse keeps blowing

The small card in the middle at the top, possibly under a metal cover.
There will be a wide flat cable going from the mainboard to it.

OK thanks. I understand.
let's check the fuse and U202.
I'll let you know.

[budm]

Re: Samsung LE37A336 TCON fuse keeps blowing

Please provide good clear pictures of the whole backside of the TV showing all the boards using 'Go Advanced'.

[Davi.p]

Re: Samsung LE37A336 TCON fuse keeps blowing

check the.diode near the fuse...