Samsung lns4692dx/xaa hdmi issue

[ibgm]

Hey guys- I have this Samsung LNS4692DX/XAA and I can't get the HDMI inputs to work. Whenever I plug something in to them, it just flashes that it is searching for a signal. I did a hard reset. I'm pretty sure I did it right because it zeroed the hrs on the screen. Anyway, I took pictures of the 2 boards that I think would be involved and was wondering if there is anything I can do to get this up and working again. The Composite inputs work, but the picture looks a bit grainy, not awful, just not as sharp as I think it should be. Appreciate any advice I can get.

Jim

[ibgm]

Re: Samsung lns4692dx/xaa hdmi issue

More clues....
On the main power board:
upper left side, copper pads with voltages marked:
PFC- 385V actual = 338V (too low)
12V actual = 11.7V
120V actual = 120.8V
VCC 20V Actual = 67.8 VAC

on right side of power supply mid board, near ribbon cables, copper pads again

12V actual = -.033V
5V actual = 5.35V
13V actual = 13.68V

That's all I got for now. Thanks for listening.

[niblettr]

Re: Samsung lns4692dx/xaa hdmi issue

I'm fairly new to this forum and TV repair but hey, I'll try and help where I can. So you have picture from what I read? I guess normal terrestrial TV works too? If so, i'm curious as to why you were looking at the main power board for a fault, especially the high voltage signals?

I'd more inclined to concentrate of the A/V board itself. Insert the HDMI plug in and out and gently twist at the same time to maybe clear corrosion out of the HDMI socket. (once worked for me, one HDMI socket fixed them all) Check for corrosion on the pin of the socket (inside and on the PCB end)

Has this board been repaired/modded before? It looks like it been back in an oven and reflowed. (discoloured white labels)

[niblettr]

Re: Samsung lns4692dx/xaa hdmi issue

The 12V that you are measuring on the power supply (and getting 0v) are you able to isolate that wire going to the Control board and measure it again at the power supply end?

[ibgm]

Re: Samsung lns4692dx/xaa hdmi issue

I've tried twisting the connectors and even a factory reset, I picked this at the local dump, I would like to get it going for my living room! The screen is in perfect shape and the service menu said the screen had just over 4000hrs on it. Is 4000 a lot for these screens?
Anyway, I will try and double check that 12V, I just figured that since it's marked on the board, I should start there. Not much info on this model out there and I really don't want to spend $100 on a tv I don't know anything about.

Thanks for the reply though, I was hearing crickets on this end!
And yes, I can watch DVD's through the Component and Composit inputs and the internal tuner does work. Just no HDMI's, which, of course, are the most important. But, like I mentioned before, the picture is not as good as it should be. It's kinda like watching a non HD 480dpi (old school TV)

Appreciate any and all feedback!!

[rccrasher65]

Re: Samsung lns4692dx/xaa hdmi issue

Its, usually caused by a bad 144 pin HDMI switching IC.

[ibgm]

Re: Samsung lns4692dx/xaa hdmi issue

Would that bad IC pull the voltage down (PFC) in the Power Supply?
It's starting to look like this old girl is going back to the transfer station.

[budm]

Re: Samsung lns4692dx/xaa hdmi issue

More clues....
On the main power board:
upper left side, copper pads with voltages marked:
PFC- 385V actual = 338V (too low)
12V actual = 11.7V
120V actual = 120.8V
VCC 20V Actual = 67.8 VAC

on right side of power supply mid board, near ribbon cables, copper pads again

12V actual = -.033V
5V actual = 5.35V
13V actual = 13.68V

That's all I got for now. Thanks for listening.

What did you use for the meter GND when you are making the Voltage measurement in the Primary side of the circuit?

[ibgm]

Re: Samsung lns4692dx/xaa hdmi issue

Kind of a newbie to all this, I used the chassis as the ground, not sure if that was correct or not. I was thinking that if the main board wasn't getting the correct power, then maybe that would cause the HDMI to not work..... I don't know the history on this unit, someone wrote "OK" on the p/s, that probably wasn't done at the factory.
Thanks,
Jim

[thorconstr]

Re: Samsung lns4692dx/xaa hdmi issue

I'm new, just making a post so I can ask a Sony HDMI question.