SAM LN46D630M3F one red blink won't switch on-off

[steves7839]

I've learned lots in Badcap land and its helped me to fix three FPTV's of four so far. On this one the main board seems to be the source of the trouble. This 46"LCD blinked red a few times but failed to power on. Disconnecting T-Con board made no change.

Jumpering SW-P to A5V lights the TV backlight, and all DC outputs on PSB match the legends. Except: On Mainbd CN201 pins 1-3 are labelled B18VS but measure 12.5 VDC. On the PSB those same pins in CN802 are labelled 13V/18V and also measure 12.5VDC. Now a Samsung "Fast-Track" guide for this model shows only 12V on CN201-1-3. So I concluded the PS is good. But I think this guide is for a different rev.

Suspecting the Main Bd, I heat treated and froze it with cooling spray, but no change. After I reflowed it in a toaster oven 275F for 8 min, slight change in symptom but no fix. Applying AC power turns the white light on. On/Off button makes STBY blink once and turn off. No sound or other response.

Should I expect 18V to the mainBD on a 2013 Samsung LCD?
Any suggestions for TS?

[steves7839]

Re: SAM LN46D630M3F one red blink won't switch on-off

I recently turned my attention back to this TV and would like to bump it to a current question. I bought a used BN96-19776A Main board from a TV shop off ebay. Shopjimmy says it's compatible. The symptoms were pretty much the same. Backlight works when Main harness is disconnected from PSB. Standby LED is red until I turn on the set, then no LED, sound or BL. No sign of emblem with the flashlight test. I barely heard a relay click on the PSB when turned on, nothing after. However, just twice the status LED gave two short then one long blink.

I think I just bought a nonfunctional main board. Can anyone suggest a confirmation test?