Need Help Troubleshooting a Sanyo DP50740

[gogettemguy]

So i picked up the Television from a friend of mine who had the TV since day 1, no problems with it at all... then one day, poof... and it sat in a closet for a few months till i got my hands on it.

All signs were pointing towards a dead PSU, plug it in, and turn it on, relays fire, and a few seconds later, the On LED goes out, you can press the Power button a total of 3 times, afterwards the LED will not respond.

I had replaced the PSU on a whim of that being an issue even ordered it before i dragged the TV out of the closet. (new PSU was from a damaged display, stated that it did light up) but i guess i have bigger issues on my hands)
All capacitors seem to be in good shape,
so far i've disconnected each lead going around the circuit boards individually in hopes for a change, yet nothing... i get 15v coming out of the PSU but immediately drops to 0v.

Attached are photos of the Television, im wondering what my next step should be...

[PlainBill]

Originally Posted by gogettemguy

So i picked up the Television from a friend of mine who had the TV since day 1, no problems with it at all... then one day, poof... and it sat in a closet for a few months till i got my hands on it.

All signs were pointing towards a dead PSU, plug it in, and turn it on, relays fire, and a few seconds later, the On LED goes out, you can press the Power button a total of 3 times, afterwards the LED will not respond.

I had replaced the PSU on a whim of that being an issue even ordered it before i dragged the TV out of the closet. (new PSU was from a damaged display, stated that it did light up) but i guess i have bigger issues on my hands)
All capacitors seem to be in good shape,
so far i've disconnected each lead going around the circuit boards individually in hopes for a change, yet nothing... i get 15v coming out of the PSU but immediately drops to 0v.

Attached are photos of the Television, im wondering what my next step should be...

A close up of the power supply might be helpful. Also, pictures of the two labels on the back of the plasma panel might help.

PlainBill

[Sleblanc]

Hi there,

I too have the same problem as described in the original post. We've changed the PSU, but we get the same problem.

Since the original poster did not reply with the pictures asked for, I will provide those I have taken from the PSU itself and the two stickers at the back of the panel.

I will provide a link to the images, because they are too large to include directly in this post.

http://www.atelierinfo.net/SANYO1.JPG
http://www.atelierinfo.net/SANYO2.JPG
http://www.atelierinfo.net/SANYO3.JPG

Any help would be greatly appreciated. Thanks.

[PlainBill]

Originally Posted by Sleblanc

Hi there,

I too have the same problem as described in the original post. We've changed the PSU, but we get the same problem.

Since the original poster did not reply with the pictures asked for, I will provide those I have taken from the PSU itself and the two stickers at the back of the panel.

I will provide a link to the images, because they are too large to include directly in this post.

http://www.atelierinfo.net/SANYO1.JPG
http://www.atelierinfo.net/SANYO2.JPG
http://www.atelierinfo.net/SANYO3.JPG

Any help would be greatly appreciated. Thanks.

Due to what might be an excess of caution, I won't access pictures hosted offsite. My favorite picture viewer and resizer is Vueprint. It's small, fast, and best of all, free; note the serial number posted on the page. Also, you MIGHT be able to attach them directly by using the URLs you used above.

PlainBill

[KTMLew]

Let me try this again...his links were safe.

[PlainBill]

Standard first step: With all cables hooked up, check the output voltages of the power supply to see if any fail to come up. Start with the cables running from the power supply to the sustain boards. If a power rail going to a sustain fails to come up, try disconnecting the cable and rechecking. Next step - check any fuses on the sustain boards.

PlainBill

[Sleblanc]

Thanks for the answers.

There's been a couple of developments in this. I've unplugged everything except the following boards on the original poster's first picture: central board, plus the two underneath.

I unhooked the right one with all the connections to the plasma screen. Same with the three left ones, and the two bottom ones. The result: the TV no longer shuts down.

I then hooked in the right board, and tested, it still worked. I tested this hooking one cable at a time. Eventually, I was able to come up with only 4 cables still unhooked: top one on the left board (the cable that goes all the way to the right board), the central cable on the left board (the one connected to the central power board), the ribbon at the bottom of the left board that goes to the smaller central panel, plus the small ribbon that connects the two bottom boards.

I figured that the TNPA5063 board must be the problem. I don't understand why the ribbon connecting the two bottom boards also causes the issue, and am not sure if I should order a replacement TNPA5063 board because of that extra cable that causes the screen to shut down.

Also, the two left pannels which are connected to the plasma panel are currently hooked into the TNPA5063 board, without problem.

Anyone has any ideas?

EDIT: After verification, the two bottom boards are the buffer boards (TNPA5079 and TNPA5080). I still don't understand why the screen would shut down when these two are connected together however.

[cptsheffield]

i have the same issue. Just wondering if you ever found out what was the problem

[googunhammer]

Has anyone fixed the issues with the DP50740 restarting problem?

[drpj23]

I have had this Sanyo have similar problems. Mine, more particularly, was the TV cutting on and the screen staying primed for about 30 seconds and then it would restart. I found disconnecting the main from the controller board (via LVDS) stopped the resetting. Eventually, I found the main was the issue (also the only part that wasn't Panasonic's) but unfortunately, I did not isolate the problem on the main board due to being under a time constraint. Hope that helps somewhat.

[llcoolt99]

Drpj23 is your tv fixed and still running after replacing the main board. Mine is doing the exact same thing as yours (rebooting every 30 seconds and won't reboot when I disconnect the LVDS). Just wanting to know if it was worth spending the $100 for the main board part. Thanks