Sanyo Plasma Display Problem Dp50747

[MagicSmoke]

Got the no picture fixed, but now on power up this happens. (1 min video)

https://www.youtube.com/watch?v=xSewl8OINrA

It will go away as it warms up, but even on highest brightness setting display (static, no antenna) is still kinda dim.

Searched for a thread with this problem, but not sure how to describe it. It's like a curtain rising or ?????

Would this be a X or Y main problem,Y buffers or bad screen. Checked all volts and they are right on what panel sticker indicates.

[KevinCro]

Re: Sanyo Plasma Display Problem Dp50747

Did you replace any boards?

[MagicSmoke]

Re: Sanyo Plasma Display Problem Dp50747

No have not replaced anything yet. Found in dumpster w/ repair tag that said no picture.

Tested all volts, VA, VS , Vscan and VE. all match with sticker on panel. All other volts match legends on PSU, 5v, 12v,etc. and they are stable.

Reseated all of the ribbon cables and power wires and got the static on screen but with the problem shown in the video. The black curtain rising. Checked all fuses (good) No obvious bad caps or other components.
I will recap the PSU with better caps if I can get the problem sorted.

The other thing is that it's not very bright even w/brightness all the way up.

Don't have a scope to test further, have searched on youtube and google for something similar, but have not come close.

[KevinCro]

Re: Sanyo Plasma Display Problem Dp50747

The problem is likely in your y sustain or z sustain boards. I had a tv with the same issue. I had to take two y sustain boards and make one good one. It worked but I was never exactly sure what actually fixed it. I would try replacing the y board, but it's risky because there might be a problem elsewhere that will blow the new board. Without a way to narrow the problem down further, you are gambling.

[MagicSmoke]

Re: Sanyo Plasma Display Problem Dp50747

Thanks for the tip. I found an X or Z main board for 15$ I will try first.

If that doesn't work then I will have to try to diagnose and fix the Y board, they are hard to find and pricey.

[tw2005]

Re: Sanyo Plasma Display Problem Dp50747

Thanks for the tip. I found an X or Z main board for 15$ I will try first.

If that doesn't work then I will have to try to diagnose and fix the Y board, they are hard to find and pricey.

if not bright and looking at the video i was thinking xmain / zsus. what boards are in it? samsung or LG?

[MagicSmoke]

Re: Sanyo Plasma Display Problem Dp50747

Everything is Samsung, panel, X & Y mains and PSU. Not sure on logic and main boards have not looked at them.

I did find one vid on utube that showed a Sanyo with a dim picture and was fixed by changing the fuse on X main.

Fuse on mine is not blown though and testing shows no shorted components.

[tw2005]

Re: Sanyo Plasma Display Problem Dp50747

Everything is Samsung, panel, X & Y mains and PSU. Not sure on logic and main boards have not looked at them.

I did find one vid on utube that showed a Sanyo with a dim picture and was fixed by changing the fuse on X main.

Fuse on mine is not blown though and testing shows no shorted components.

You said fuse, so is that 1 fuse or 4 fuses you checked?

Xmain fail on these is rare but I have read one post where one of the pico fuses went open.

I've marked the fuses.
With that panel ymain and shorted buffer is the most common fail and also cracked solder joints on the PSu if it's samsung causing erratic shutdowns and relay clicking but that is not what you have here.

Keep an eye out for bulging caps 680uf 25v on the ymain, not sure what's on the xmain

same panel,boards and image shown looks just like yours. blown fuse on xmain. did not see or read which fuse though.

https://www.badcaps.net/forum/showth...highlight=pico

[tom66]

Re: Sanyo Plasma Display Problem Dp50747

Have to agree with X-main looks similar to low Ve voltage on X-main side.

[tw2005]

Re: Sanyo Plasma Display Problem Dp50747

Actually the fuse was mentioned in that post. The pico fuse right next to the ceramic where the power inputs are. F4702 1A 125V pico

The menu looks great and just as a follow up there are two of those resistor style fuses in addition to the standard glass fuse on the xmain. The one that failed was the small resistor fuse located directly next to the glass fuse. I am watching Netflix on the t.v picture looks great and already have a buyer lined up.

[MagicSmoke]

Re: Sanyo Plasma Display Problem Dp50747

Thanks for that info tw2005. All I checked was the large main fuse. Did not know about the other pico fuses.

VE volts measured at test point on X main reads what sticker says. Will retest fuses.

Have not removed any boards yet to check solder joints. And I will recap PSU and the smaller caps on X & Y boards.

Forgot to mention the PSU has the same high pitched squeal as in the other thread, so I will definitely recap the power supply.

[MagicSmoke]

Re: Sanyo Plasma Display Problem Dp50747

Checked other 3 pico fuses on X main and none are blown. Changed the 680uf 35v cap to a 680uf 50v.

How often do the large 250v caps go bad? This thing is full of Samwha caps.

Going to pull PSU now and recap it just to make sure, it has a squeal like in the other thread. Although all volt readings are stable according to my meter.

[tom66]

Re: Sanyo Plasma Display Problem Dp50747

I've never seen those capacitors go bad on a sustain board. They're not under any significant stress.

[MagicSmoke]

Re: Sanyo Plasma Display Problem Dp50747

Can 1 bad cap cause what was happening??

I put X main back in after changing the cap...... and lo and behold no more "curtain of black" Picture brightness is good, seems to be up and running.

Still going to recap PSU. Thank You to all that took time to help me.

I guess the TV tech that looked at it before it went into the dumpster might need to come here and learn something.

[tw2005]

Re: Sanyo Plasma Display Problem Dp50747

Checked other 3 pico fuses on X main and none are blown. Changed the 680uf 35v cap to a 680uf 50v.

How often do the large 250v caps go bad? This thing is full of Samwha caps.

Going to pull PSU now and recap it just to make sure, it has a squeal like in the other thread. Although all volt readings are stable according to my meter.

Interesting, have to say i was expecting a blown fuse. Larger CAPs usually seem to last ok, but I've never tested them nor do I have an ESR meter.

Probably not economic to replace the big caps?

If you've got another xmain coming hopefully that fixes it. So what are the voltages like at the Xmain at CN4701, Vs, Vcc, testpoint Ve?

[tw2005]

Re: Sanyo Plasma Display Problem Dp50747

Can 1 bad cap cause what was happening??

I put X main back in after changing the cap...... and lo and behold no more "curtain of black" Picture brightness is good, seems to be up and running.

Still going to recap PSU. Thank You to all that took time to help me.

I guess the TV tech that looked at it before it went into the dumpster might need to come here and learn something.

Oh, nice surprise, so are we talking about a 680uf cap on the X?

[MagicSmoke]

Re: Sanyo Plasma Display Problem Dp50747

I was expecting a blown one also, but see above post.

Thank you tw2005 for taking time to point me in the right direction.

Edit, Yes the only low voltage cap on the X board. 680uf 35v.

Yeah should have waited to buy anything, but it was only 15 bucks.

[tw2005]

Re: Sanyo Plasma Display Problem Dp50747

I was expecting a blown one also, but see above post.

Thank you tw2005 for taking time to point me in the right direction.

Edit, Yes the only low voltage cap on the X board. 680uf 35v.

Cool, yeah I have a new x here from working on a couple in the past, I did not bother to check what caps it had but I know those on the ymain do bulge and cause issues.

Can't say that was my expectation here but only mentioned it because I saw the smaller cap in the image and wondered.

I guess it showed no physical signs of being bad?

I love the simple cheap fixes.

[tom66]

Re: Sanyo Plasma Display Problem Dp50747

Could be that the ribbon cable for X-main drive was loose/poorly seated. This can cause the X-main to behave as if it is bad.

[tw2005]

Re: Sanyo Plasma Display Problem Dp50747

you should post up the before and after shots. I wonder if it's a good idea to replace the same 680uf on the ymain since they've done the same hours if still original?