LN46A650 problem

[truep]

The problem is as follows:
ran for 8 hours with the back off. All caps look fine but I have ordered replacements for the power supply. All voltages are stable.

Today I put the back on. It ran for 3 hours then the screen went black. Backlights are on and sound is fine. I turned it off and imediately turned it on again and it came up fine.

Sound like a tcon heat problem?

[budm]

Re: LN46A650 problem

Get a can of freeze spray or a can of air duster using it up side down to cool the T-CON board, at the same time monitor the voltage on the SMD fuse on the T-CON to see if the voltage goes away.

[truep]

Re: LN46A650 problem

The problem will be the shield around the TCON. It's used as a heat sink so I don't want to run it with the shield off. I'll try it tomorrow with the sheield on. The tcon does get very hot. I'll try heating the main board too just in case.

[tom66]

Re: LN46A650 problem

You could rip heatsinks off old motherboards and leave the shield off. They will work better anyway.

[budm]

Re: LN46A650 problem

Does the shield actually make contact with the ICs, or has any heat transfer pads?

[tom66]

Re: LN46A650 problem

I have worked on the LE40A656 twice which is the same TV, but UK version, and the frame is used as a heatsink. I have had once case of overheating chip on the T-con.

[truep]

Re: LN46A650 problem

There is a heat transfer pad. The set runs fine with the back off (10 hours) so it's a heat problem.
The only thing on the set that gets hotter than warm is the TCON.