Help needed finding bad board on Sanyo Plasma DP50747 TV

[copycat]

I need help finding which board I need to repair.
This TV is a 50 inch sanyo plasma model dp50747
Tv went out right after some stormy weather.

When I power it on. I hear it click on, then 2 seconds later I hear a another click, After the second click the logic board lights( only 3 lights lit) goes out then 30 seconds later the light on front goes out. Screen never comes on.

here's what I did so far.
I removed 4 fuses and tested them with a volt meter, all good
Didn't see any signs of bad caps or burnt components.
I disconnected Y & Z sustain boards one at a time, then powered unit on. No change.
I need help measuring the voltage on the power board but I'm confused...I see 3 VS pins and 2 VA pins. I got my volt meter on 200dcv, black lead on GND pin and the red on either Vs or Va but which one. How can I measure it accurately when turning on if it shuts off in 2 seconds. Any help?

Thanks
Bill

[capkid]

Re: Help needed finding bad board on Sanyo Plasma DP50747 TV

You need to check VS and VA. Place your positive lead on one of the VS or VA pins, respectively, then place your negative lead on a metal part of the chassis.

Edit: Sorry, I had to reread your post. I'd try disconnecting the main board from the control board.

[copycat]

Re: Help needed finding bad board on Sanyo Plasma DP50747 TV

main board from the control board?...you mean logic board and main board?

Thanks,
Billl

[tom66]

Re: Help needed finding bad board on Sanyo Plasma DP50747 TV

Main board has video inputs.
Control board has the LEDs on it.
Can you post a picture of your control board?

[copycat]

Re: Help needed finding bad board on Sanyo Plasma DP50747 TV

got it...

logic board (control) is behind the main board. Logic board is a rectangle shape and has the 3 LEDs the light up. I will try to get a better picture soon. Thank you for helping!

[copycat]

Re: Help needed finding bad board on Sanyo Plasma DP50747 TV

I've read somewhere I could disconnect all cables off the power board except the main AC connector then read Va & Vs voltage. If power board still shuts down or voltages don't match on the sticker inside then problem is with this power board.

I was thinking either power board or main board are the problem.

Thanks
Bill

[capkid]

Re: Help needed finding bad board on Sanyo Plasma DP50747 TV

Let us know the results of your tests.

[copycat]

Re: Help needed finding bad board on Sanyo Plasma DP50747 TV

here's what happened when I unplugged all cables from the powerboard except on board AC power.
Once I plug the powercord back in I hear a 1 click, then in 2 seconds I hear another click. This is without pushing the power button. Still cannot measure Vs, Va because it's keeps shutting down. The 2 black relays on the power board are the ones making the clicking. Would a normal working power board click once and stay on? I shouldn't get a second click on the relays.

Now I believe this board is bad because its keeps shutting down. Can someone confirm this?

I also measured the AC voltage from the brown power filter board to power board. It's 123v, shouldn't this be 110v?

thanks
Bill

[capkid]

Re: Help needed finding bad board on Sanyo Plasma DP50747 TV

I believe the PSU shuts down when it's initially plugged in then you have to turn on the TV. Did you try disconnecting the main board from the control board, leaving everything else intact?

[copycat]

Re: Help needed finding bad board on Sanyo Plasma DP50747 TV

ok.
I put all cables back and disconnected cable from control board to main board. Results are the same. Power board clicks once after turned on than after 2 secs clicks again. Control board has 3 lights lit until second click shuts them off. Power LED on front screen stays lit for about 30 secs after second click. Nothing on plasma screen..

Also tried this same test but with power disconnected from X & Y boards.. Same results except control lights never come on.

thank you for your help.
Bill

[capkid]

Re: Help needed finding bad board on Sanyo Plasma DP50747 TV

Yeah, it sounds like your PSU is faulty. I wouldn't rule out the main board just yet, also. You might have to test to see which PSU voltages start to come up before it shuts down and which don't. Are you able to power on the TV repeatedly with the remote (I understand that it shuts off in 2 secs)?

[kevinm34232]

Re: Help needed finding bad board on Sanyo Plasma DP50747 TV

What's the chassis # on this TV, DP50747-XX??

[copycat]

Re: Help needed finding bad board on Sanyo Plasma DP50747 TV

here's the voltages before shutting down. Sometimes a little higher or lower if I do a second reading. When It does shut down, I cannot turn until after 30secs, after the third try I'm locked out. Have to unplug power for a few minutes. Still think it's the power board?
Vs- 38v
Vs- 37v
Vs-32v
Va-6v
Va-4v

chassis number is DP50747-00 from outside cover.