PS51D6900 sound no picture

[satinser]

Sorry forgot to mention in heading Samsung.
Originally the fault was standby led flashing with no picture. Found that control board ( LJ41-09390A ) had a blown chip u2005 (D9153) obtained a replacement control board. When fitted tv now powers up ok with green led on control board flashing once a second but still no picture or any illumination of the screen whatsoever. Any help appreciated

[satinser]

Re: PS51D6900 sound no picture

I forgot to mention that ive tried forcing test signal by shorting pins 3 and 4 on logic main but with no response screen still dark with no illumination.
I would also mention VS and VA voltages on test points on PSU read as correct on panel sticker. VSC voltage on test point on Ysus also reads correct as panel sticker. VE voltage on Xsus test point however should according to panel sticker read as 80 volts and this is way out of range at 195 volts.
Ive tested all FETs on both ysus and xsus and found them all to be ok. I managed to source both ysus and xsus for a good price so went ahead and ordered both boards. After fitting both replacement boards I still have the same fault so either the fault is not on those boards or replacement boards have the same fault.
As regards the incorrect VE voltage I found that on both sets of boards both originals fitted and replacements VE voltage 195 volts instead of the correct 80 volts.
As regards the Ybuffer board all chips have been zip tested with no shorts.
Anyone any ideas?

[dick_barton]

Re: PS51D6900 sound no picture

When you tested by shorting the two pins, did you remove the ribbon connection from the logic board to the mainboard?

[satinser]

Re: PS51D6900 sound no picture

Thanks for your reply. Yes I did

[dick_barton]

Re: PS51D6900 sound no picture

Thanks for your reply. Yes I did

Did you have a steady blink on the Logic board?

[dick_barton]

Re: PS51D6900 sound no picture

Thanks for your reply. Yes I did

Did you have a steady blink on the Logic board?

[Andrew F. Ali]

Re: PS51D6900 sound no picture

Did you have a steady blink on the Logic board?

A steady 1-blink on the Control Bd would indicate a working board.. Verify all connectors were properly reconnected.

[satinser]

Re: PS51D6900 sound no picture

yes steady blink of 1 green flash a second.
I think i may have the answer When I replaced the Logic board i purchased from an ebay seller. In his listing it was down as from PS51D6900 Ive just checked the green barcode sticker and found that the code is TL 753B which is actually for PS51D550. The correct Logic board for the PS51D6900 has code of TL 756A. Visually there identical except for a different software sticker on chip u2002.
Have ordered the correct one now and hopefully this will resolve the issue.

[Andrew F. Ali]

Re: PS51D6900 sound no picture

I have found TVs with the same model nos. that have different Logic Bds. and in LCD TVs different T-CON Bds. I think this is due to the fact that same model TVs have different Panels and so these parts would be different. So I think the Seller did not sell you a wrong part. The onus was on the Buyer to match the nos. to ensure he was buying the correct part.