Sanyo DP42849-01 No Picture

[kevinm34232]

Picked up this TV from someone used to be in the business, says he had another of same model that was working and swapped PS boards and both TV's worked with the working PS board.

The TV looks to be dead on plug in, no standby light but I found out all voltages were present, 5v, 12v, audio 15v. Inverter circuit is built into PS board. When powered on, green LED comes on and TV does not shutdown, but no pic, sound or backlight. Shining a light into screen does not show any video.

On PS Board, when powered on there is no voltage at BL-ON pin.

From what I can find from other repairs, it seems like the main board is the problem. However because of what I was told by the seller and the fact that the TV does not shutdown from a power failure circuit, wondering if it is something in the PS. And strange that there is no red standby LED..

Is there some feedback from the inverter circuit happening before BL-ON?

[kevinm34232]

Re: Sanyo DP42849-01 No Picture

Couple of a lilttle clearer pics before I get yelled at

[budm]

Re: Sanyo DP42849-01 No Picture

It does sound like the problem is in the main board since the power supply in this TV works OK in another working TV. The BL_ON is from main board, it has to be sent to the inverter first to try to turn it on, then any error signal if it is used in this TV will be feedback back to the main board if there is problem with the inverter section.

[selldoor]

Re: Sanyo DP42849-01 No Picture

When powered on, green LED comes on and TV does not shutdown, but no pic, sound or backlight. Shining a light into screen does not show any video.

You have got a source connected ?- video with sound running or something.
Sound may also have been muted prior to breakdown and stays muted.

[kevinm34232]

Re: Sanyo DP42849-01 No Picture

Well I had all voltages expected at main board, not sure why I wasn't getting BL-ON so I decided to jump BL-ON from a 3.3v source on the main board. Backlight comes on for a few seconds (long enough to see LCD screen is cracked ), and then goes off.

So now I don't know what boards are good unfortunately.

[kevinm34232]

Re: Sanyo DP42849-01 No Picture

If I jump BL-ON and BL-DIM with 3.3v backlight comes on and stays on, but no signal from main board without jumping. Since LCD is found cracked, could there be a signal coming from T-Con board to not give the BL-ON? Or could T-Con be bad too?

[henrysin44]

Re: Sanyo DP42849-01 No Picture

I'm having the same problem, what did you jump blon and bldim to?