Samsung LN40D630M3FXZA Has Backlight and Sound, No Picture

[tom66]

Re: Samsung LN40D630M3FXZA Has Backlight and Sound, No Picture

Yeah, looks like it. Sad to see another panel bad!

[kevinm34232]

Re: Samsung LN40D630M3FXZA Has Backlight and Sound, No Picture

I've seen those looking for what part # QD2 is on many Samsung T-Cons. I replaced the shorted QD2 on the original T-Con with part# ZXMN6A07FTA MOSFET N-CH 60V 1.2A SOT23-3, and it worked. Unfortunately it confirmed the panel is bad as the image was same as above.

[tom66]

Re: Samsung LN40D630M3FXZA Has Backlight and Sound, No Picture

Panel might have initially caused fault, then whatever was shorted went open circuit. Transistor was damaged in that fault condition.

[nomoresonys]

Re: Samsung LN40D630M3FXZA Has Backlight and Sound, No Picture

I've seen those looking for what part # QD2 is on many Samsung T-Cons. I replaced the shorted QD2 on the original T-Con with part# ZXMN6A07FTA MOSFET N-CH 60V 1.2A SOT23-3, and it worked. Unfortunately it confirmed the panel is bad as the image was same as above.

too bad about the panel but a very nice tcon fix.

[pudgi300]

Re: Samsung LN40D630M3FXZA Has Backlight and Sound, No Picture

would anyone know the p/n for the fet with marking 58A. It is used on many tcon boards. It is p-ch 6pin

Thanks

[pudgi300]

Re: Samsung LN40D630M3FXZA Has Backlight and Sound, No Picture

Looks like i tracked it down to FDC658A made by fairchild.

I got my Sony KDL-40w4100 Tcon board working after replacing the following parts.

F1 7amp fuse

cd 201 10uf cap

D14 sot-23 switching diode marking KJH MMBD7000 DIODES INC 2 DIODES IN SERIES (1 WAS LEAKING)

IC11 FDC658a digikey FDC658APCT-ND


I ALSO REPLACED IC21 TPS65167A BUT ONLY REPLACE IT IF IT IS BAD. I FOUND ONE ON AN OLD MITS TCON MADE BY SAMSUNG.

HOPE THIS HELPS SOMEONE REPAIR THEIR TV

[Recyclojunk64]

Re: Samsung LN40D630M3FXZA Has Backlight and Sound, No Picture

Hi, I am trying to repair a Hisense HL46T39PZLN3D LED-backlit display with a similar problem.

Transistor QD1 on T-con board SD120PBMB4C6LV0.0 is not turning on (12V on gate), it's gate capacitor is not shorted, and transistor QD2 is not shorted/burned. I could not figure out where the gate-signal for QD1 goes to as the trace disappears into the middle layers of the board and couldn't find a connection.

I attached a wire to temporarily bypass QD1 just to see if the panel is damaged before ordering a replacement T-con board (or trying further to repair the existing one). I connected the wires after the TV had turned on, and this is what comes up on the panel:



After about 30 seconds it slowly fades to this:



Then goes back to the original as soon as the jumper wires are disconnected and reconnected.



Is it likely to be a problem with the display panel? Or simply because the T-con board was not initialised properly? I don't have that much experience repairing TVs so don't really know what a defective panel looks like.


Thanks for any advice.

Edit: Full size images below.

[Recyclojunk64]

Re: Samsung LN40D630M3FXZA Has Backlight and Sound, No Picture

Hmm..., noone has seen an LCD displaying a pattern like this before? I would really like to know whether it's worth replacing the T-Con board to see if that fixes it or whether these are the symptoms of a failed panel and I should just toss it to make more room on my workbench.

I have a digital scope btw if there's anything else I could test for...

[steves7839]

Re: Samsung LN40D630M3FXZA Has Backlight and Sound, No Picture

Sure looks like a T-Con symptom. I'd buy one from a seller accepting returns if possible.