Sanyo DP50747-00 Plasma No Video Good Audio

[kevinm34232]

Sanyo DP50747 Chassis 00

Panel: Samsung S50HW-YD02

Symptoms: TV powers up and stays powered up, have audio, but no video. Tried to look for a 'glow' but best I can tell there is nothing. It's pretty bright in here so I rolled up some black construction paper and made a tube out of it but saw no change in lighting.

I did see one or two random lights kinda shoot around the screen for a second on power up.

I have not repaired a plasma yet and am actually surprised and pleased that this one powers on and stays on with audio. I had a Sanyo 50747-04 before that shut down with a main board PFC and never figured it out.

This would be my first real attempt at a plasma repair so I'm looking forward to learning more about it...

I do not have a scope BTW... Thanks!

[tom66]

Re: Sanyo DP50747-00 Plasma No Video Good Audio

First step is to measure Vs and Va on the PSU, and compare them to the panel sticker ratings.

[kevinm34232]

Re: Sanyo DP50747-00 Plasma No Video Good Audio

Sticker:
VA=63
VS=205

Reading off PS:

VA=63.2
VS=206
VG?= 15.05

Going to eat will be back soon.. Thanks!!

[tom66]

Re: Sanyo DP50747-00 Plasma No Video Good Audio

Good voltages, close enough. There are fuses on the Y-main and X-main. Check those for continuity, and replace them if they have failed. If the TV then fails to power up, or the fuse has failed, you likely have the common 88N30 FET failure; one buffer IC may need replacing too.

[kevinm34232]

Re: Sanyo DP50747-00 Plasma No Video Good Audio

Both fuses are good. Where are the FET's to check?

[tom66]

Re: Sanyo DP50747-00 Plasma No Video Good Audio

If the fuses are good, it's not the FETs.
Suspect the control board.
The LED on it should blink.
Does it?

[kevinm34232]

Re: Sanyo DP50747-00 Plasma No Video Good Audio

Was just poking around aimlessly and discovered...

F5700 is open..
R5009 reads about 40k ohms..

[kevinm34232]

Re: Sanyo DP50747-00 Plasma No Video Good Audio

Yes LED blinks on control board

[tom66]

Re: Sanyo DP50747-00 Plasma No Video Good Audio

It looks like C5708 is bulging to me.

[kevinm34232]

Re: Sanyo DP50747-00 Plasma No Video Good Audio

You're right it's under the heat sink but it is bulging (c5709). F5700 has 1A LF (Littlefuse) on it, and R5009 has 4 bands, brown, black, yellow and gold and resisitor is cyan in color. Can you give me possible replacements for the fuse and resistor??

Is it likely to just be those components? Did not find any replacement Y Mains with a quick search.

[tom66]

Re: Sanyo DP50747-00 Plasma No Video Good Audio

I've done the 42" of this chassis (Samsung branded though) and had the same cap bulging in a different area, it causes the Y-Main to stop working, and give you no image at all. 100uF 50V, I guess?

Replace the fuse with any 1A through hole picofuse; what rail does it connect to? Probably for the 15V rail.

[tocold4u2]

Re: Sanyo DP50747-00 Plasma No Video Good Audio

10x10k=100k5% brown=1 blk=0 x yellow =10k gold= 5% i think this is right but ask others to make sure

[tom66]

Re: Sanyo DP50747-00 Plasma No Video Good Audio

Yeah I think it's 100k too. 40k is in circuit. It's probably fine.

[tocold4u2]

Re: Sanyo DP50747-00 Plasma No Video Good Audio

i got a pk of resistors and it shows on the back how to figure them,,,,,,,which is helpful!!

[kevinm34232]

Re: Sanyo DP50747-00 Plasma No Video Good Audio

Without pulling it out it looks like its a 25V 680uF cap.

[tom66]

Re: Sanyo DP50747-00 Plasma No Video Good Audio

The one I replaced was 100uF 50V, but they may have changed the design.

Replace the fuse.
Replace that capacitor.
See if TV works again.

[vinceroger69]

Re: Sanyo DP50747-00 Plasma No Video Good Audio

http://www.diyalarmforum.com/4-band-resistor-calc/

[kevinm34232]

Re: Sanyo DP50747-00 Plasma No Video Good Audio

Replaced fuse F5700 (Pico Fast 1A 125V) and capacitor C5709 (680uF 25V), TV working now, thanks Tom!!

[tom66]

Re: Sanyo DP50747-00 Plasma No Video Good Audio

So, in the end, it wasn't too difficult was it?

[kevinm34232]

Re: Sanyo DP50747-00 Plasma No Video Good Audio

Not this one at least, nothing compared to others I've seen here. I still have 1 more big Samsung in the car tho!