Sanyo DP46849

[steveh_131]

I just picked this TV up yesterday. I had a lot of fun with my last repair with the help of you guys, so I figured I'd try it out again!

And after lots of reading on this site, I was able to take apart a 26"lcd, find the bad capacitors, and solder in new ones with no help at all.

So, about this new tv:

When I plug it in, it does nothing.

I hit the power button, and a green light comes on in the front. The screen does not come on. Pressing the power button turns the green light off and on but nothing else.

I took off the panel on the back, and there are no bulging capacitors or burn marks that I can see. The fuse showed continuity with my dmm.

So far I've tested from 5V to ground on the power board with everything plugged in, and it shows 5V.

Not sure where to go from here. Any clues?

Some pics:

[newtothis]

Re: Sanyo DP46849

On the PSU can you check the BL_ON pin with DMM set to 20VDC, black probe on chassis and red onto the pin... observe the voltage when switching the set on.

Also do this for the PS_ON./OFF Pin.

[steveh_131]

Re: Sanyo DP46849

Thanks for your help once again, newtothis!

BL_ON stays at zero, whether the power button is pressed or not.

is PS_ON/OFF that white pin at the bottom?

If so, that one shows 5V when the green light is on and 0 when it is off.

[steveh_131]

Re: Sanyo DP46849

Bumping to see if anyone else has any clues. I haven't had any luck figuring this one out yet.

[budm]

Re: Sanyo DP46849

So the main board is not toggling the BL_ON High and LO. Need to troubleshoot the main board. Sch will help if you can find it.

[steveh_131]

Re: Sanyo DP46849

A little more info:

The green power light is cycling on and off on its own. I didn't notice that until today. It stays on for maybe 30 seconds then turns off for a few seconds then comes back on.

Also, I tried jumpering the bl_on pin to the 5v stdby pin and the backlight turns on, but there is still no picture.

I can't find a schematic for this board. I know I have model number dp46849, chassis 02, and the main board is the n7eg. Anyone have any idea where I can find schematics for this thing?

Unrelated: is there a way I can edit my OP to move the images to the managed attachments? After further reading I'm seeing that I should have done that from the start, so I apologize for the poorly written OP.

[jaimegmr]

Re: Sanyo DP46849

A little more info:
I can't find a schematic for this board. I know I have model number dp46849, chassis 02, and the main board is the n7eg. Anyone have any idea where I can find schematics for this thing?

Found this great site today and it has the schematic you are looking for.
http://www.toms-service-manuals.com/...h=Submit+Query
Download the Service manual for chassis 00 and then the supplement for 02. The only difference is a new LCD panel and 2 resistor changes.

[steveh_131]

Re: Sanyo DP46849

Thank you, jaimegmr.

A quick read of the service manual shows the probable repair route at the top:

SYMPTOM: If the power LED on front of the TV is turning ON for 10-20 seconds, OFF for 1-2 second and keeps repeating, the problem is most likely IC5750A. Affected models are the 2009 & 2010 TVs (LCD and Plasma) listed.

IC5750A is located under the large shield. IC 5750A is a 48 pin NAND FLASH IC with easy access for replacement. This will fix +80% of the boards with the symptom below.

Apparently it's a little IC that I'd need to order from Sanyo.

I get what it's saying about 'easy access', the solder points are pretty well isolated from other parts.... but I don't know that I have the equipment or the skill to remove and replace it. I had a hard time soldering capacitors into a power board.

[steveh_131]

Re: Sanyo DP46849

For reference for anyone else with this issue:

A new main board resolved this problem.

Thank you all for your help!

Steve