Panasonic TH-55DX640A Stuck on R-G-B to Grey Cycle

[dknei2]

Good morning everyone,

I've got a Panasonic TH-55DX640A that I picked up as a salvage unit, would love to get it going.

The unit boots into the OS, I can confirm as voice guidance works perfectly. After turning on, it cycles between a full grey display to full red, green then blue and back to grey.
Nothing other than the cycle will display.

From what I've read it seems like it's stuck in a factory test mode. I've tried a number of combinations to bring up a service menu however none have proved successful.
The odd thing is that I can get a shadow of where a display should be. In the pictures below I've got a couple of pairs of each colour. One where it's showing as it's booted, and one where I've pressed the info button. The one where I've pressed the info button leaves a shadow at the bottom of the display, where I imagine the info bar should be.

The unit is running a MediaTek MT5810PEHJ and a Novatek NT72324BG-35 LCD Controller. The board number is TNPH1120(2)(A) and the T-Con board number is 15YA2FU13TSTLTG2_V0.1. The T-Con board runs a Samsung VTU11A2.
Removing the left (as pictured) T-Con connector from the T-Con to the mainboard leaves a backlight, which makes sense as it looks like it holds the SDA/SCL line. Removing the right T-Con connector from the same doesn't appear to do anything.

Could it be that the T-Con is stuck in test mode, or is the RGB being pushed from the mainboard? I'd greatly appreciate any ideas if anyone has had experience with something similar.

[Andrew F. Ali]

Re: Panasonic TH-55DX640A Stuck on R-G-B to Grey Cycle

Looks like a Main Bd issue to me...Perhaps the EEPROM is defective or software needs updating..

[dskall]

Re: Panasonic TH-55DX640A Stuck on R-G-B to Grey Cycle

Not familiar with it. Possibly a jumper that puts it in test mode?

[dskall]

Re: Panasonic TH-55DX640A Stuck on R-G-B to Grey Cycle

Here's a post I found since you said you can see something." I managed to get out of the pattern, the main problem was that it even covered the service menu. Had to "feel" myself to the setting. The biggest problem now is that it identifies itself as an 40E4000, probably due to me accidentally changing other values looking for the setting in question."

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