Sanyo DP50747-01 no video or sound??

[fastpacket]

I'm posting this new thread hoping to see the light after a dark tunnel..!

This Sanyo TV had a problem with shutting off after a few min. I did a visual inspection on the main P/S and found 9 caps (680mf 10V) bad (the top popped). These were replaced and fixed the original symptoms of shutting the set after a few min.

We connected the set to the cable box and everything looked fine, except the video started to blink only on HD channels, regular non-HD worked ok. After a few days the video was gone and same with the audio.

Back on the bench, a visual inspection shows the previously replace caps were fine. Testing the voltages at the connectors low voltages 5v, 3.3v, 24v etc all test fine. The only connector with no voltages is CN206 stencil with Vs, Gnd, and Va. This connector extends over to the left side board; I believe this to be the YSUS board.

I replace all 6 power MOSFET transistors SD20N60, just a wild shoot on the dark, still no voltage at the Vs and Va connector.

The PDP Service Manual attached by a member of this board on a differnet thread show Vs to be 188v-198v and Va to be 56v-61v. Without a P/S manual I'm at a lost trying to trace the path for either source.

The P/S part # stencil are YPSU-J013A and LGE PN:AAX30284301.

Any help with a P/S service manual or possible solutions is appreciated it.

[PlainBill]

Re: Sanyo DP50747-01 no video or sound??

I'm getting contradictory information on this TV. Some sources indicate this is a Samsung panel, others say LG Electronics.

I understand this is a great burden, and believe me, I wouldn't ask if my crystal ball was working. Without pictures - one of the back of the TV, one of the Y-Sustain, it's difficult to give meaningful advice.

Attach pictures using Manage Attachments - below the text entry area.

PlainBill

[Dgtech]

Re: Sanyo DP50747-01 no video or sound??

By your description of the repair done, you replaced only the visually bad caps. If this is the case, I'd advise to go all the way with the cap replacement. Make sure that these caps are low ESR caps when you order them.

[fastpacket]

Re: Sanyo DP50747-01 no video or sound??

PlanBill,

I'm attaching several shoots of the rear as you requested. The P/S is missing from these pictures as I have it on the work bench, so a separate snapshoot is included.

The YSUS is listed as LGE PN:EAX34151601 Rev C and the ZSUS is listed as LGE PN:EAX34151801 Rev B.

I circled the items replaced on the P/S, the blue circles shows the MOSFET replace all are the same , the white circles shows the replace set of caps, and the red circle shows the CN206 with Vs and Va stencils.

Hope this helps...!


Dgtech,

The P/S caps were replaced with same specs as the previous ones. I made a small error these are 3300nf @ 10V, not 680mf @ 10V on my initial post.

Thanks

[PlainBill]

Re: Sanyo DP50747-01 no video or sound??

PlanBill,

I'm attaching several shoots of the rear as you requested. The P/S is missing from these pictures as I have it on the work bench, so a separate snapshoot is included.

The YSUS is listed as LGE PN:EAX34151601 Rev C and the ZSUS is listed as LGE PN:EAX34151801 Rev B.

I circled the items replaced on the P/S, the blue circles shows the MOSFET replace all are the same , the white circles shows the replace set of caps, and the red circle shows the CN206 with Vs and Va stencils.

Hope this helps...!


Dgtech,

The P/S caps were replaced with same specs as the previous ones. I made a small error these are 3300nf @ 10V, not 680mf @ 10V on my initial post.

Thanks

That's definitely an LG design, but not one I'm familiar with.

3300 nanofarads??

PlainBill

[fastpacket]

Re: Sanyo DP50747-01 no video or sound??

That's definitely an LG design, but not one I'm familiar with.

3300 nanofarads??

PlainBill

Oops typo 3300mf...!

[Dgtech]

Re: Sanyo DP50747-01 no video or sound??

If I were you, I'd finish replacing the rest of the caps. If you found 9 visually bad, I would think that all are either bad or close to it. They can be bad without being visually bad. If you go forward troubleshooting without clearing the obvious possible solution first, you'll end up spinning your wheels.

[madmike56]

Re: Sanyo DP50747-01 no video or sound??

I am having a similar problem with the dp50747. I replace about 8-9 caps on the p/b and all worked great for 10 days, then no sound or video; the screen glows. the p/b comes on and the smaller board to the left and below it has 3 green leds lit when powered on. and ideas? I am buried in this set
many thanks
Mike in Tucson

[madmike56]

Re: Sanyo DP50747-01 no video or sound??

I am having a similar problem with the dp50747. I replace about 8-9 caps on the p/b and all worked great for 10 days, then no sound or video; the screen glows. the p/b comes on and the smaller board to the left and below it has 3 green leds lit when powered on. and ideas? I am buried in this set
many thanks
Mike in Tucson

I really need help... when I power up this set that worked fine a week ago it has a dull glow on the screen and no audio or menu display. I see the "logic " board has 3 leds lit up...D3 on D4 on D5 on....can anyone please help?
thanks in advance
Mike in Tucson

[PlainBill]

Re: Sanyo DP50747-01 no video or sound??

I really need help... when I power up this set that worked fine a week ago it has a dull glow on the screen and no audio or menu display. I see the "logic " board has 3 leds lit up...D3 on D4 on D5 on....can anyone please help?
thanks in advance
Mike in Tucson

That is a power supply or main board problem. I Googled DP50747 schematic and got hits from the usual (pay) sites. One may be available at keepandshare.com; something about the site rang my alarm bells. Use your own judgement.

Other than that, I suggest the usual procedure. If the output voltages of the power supply are labeled, verify all the voltage, especially those below 20 volts. Several repair services for the power supply are on eBay, that would tend to indicate a power supply problem.

PlainBill

[madmike56]

Re: Sanyo DP50747-01 no video or sound??

thank you very much bill. as I expected..power board. I noticed a small cap that is bad that either wasn't bad before the repair or has gone bad since. I am a little leary of some of the vendors on ebay (and well should be)
this set contains many LG boards, including the PB.
I'll let you know what I find out. I don't suppose you repair these boards?
just a thought..

[PlainBill]

Re: Sanyo DP50747-01 no video or sound??

thank you very much bill. as I expected..power board. I noticed a small cap that is bad that either wasn't bad before the repair or has gone bad since. I am a little leary of some of the vendors on ebay (and well should be)
this set contains many LG boards, including the PB.
I'll let you know what I find out. I don't suppose you repair these boards?
just a thought..

Other than for my own purposes, I rarely do component level repair. My standards require testing the repaired part; it's impractical to ship a 50" plasma TV.

PlainBill

[ripster]

Re: Sanyo DP50747-01 no video or sound??

I have a quick ? for the 680uf under the bank of 3300uf's on the right side. I got a replacement today for the 680uf. The old one has the silver strip with a "-_ign. The new replacement has the silver strip with an "0" sign. Are they the same or is it positive and negitive?

[dumpystig]

Re: Sanyo DP50747-01 no video or sound??

The 'silver line' is always negative (-) on an electrolytic. And elctrolytics are polarised so should be connected correctly in circuit.

[ripster]

Re: Sanyo DP50747-01 no video or sound??

Thanks! That's what i was thinking but the "0" had me confused.

[dumpystig]

Re: Sanyo DP50747-01 no video or sound??

No prob. Are you sure the O doesn't also have a - contained within?

[ripster]

Re: Sanyo DP50747-01 no video or sound??

We have TV! But im back to square one because im still waiting for the 3300uf and a 1000uf. But i can watch TV until they get here.

[fastpacket]

Re: Sanyo DP50747-01 no video or sound??

OK folks,

I’m re-opening my thread once again after further troubleshooting.

So far I had the P/S repair and all seems to be ok, however one note on the voltages from my previous post.

The Va and Vs (57V and 190V) are now present if the P/S connector P800 (AC-O, RL-ON, 5V sb, DET, Vs-on, 5V-D and GND) which goes to the Main Board @ K6P is removed. If the connector is in place after powering the set the Vs and Va drop down to about 1.5V.

In reading other threads on this model the indication on the Ctrl board LEDs for a working set should be D2-D5=off D3-D4=on. However my Ctrl board has D2=off and D3-D5=on.

Logic dictates there could be a problem with the Main board may be shorting/disabling the Vs-on pin back to the P/S, but with D5=on it could well be the Ctrl board too?

What fault would a D5=on represent?

Any suggestions?

[CAZ3]

Re: Sanyo DP50747-01 no video or sound??

Same issue as above except I cannot get above 2V on Vs and 1V on Va with or without P800.

Thoughts?