Hi All!
This one got me stubbed, I found this NEC X551S Digital Signage display at my local recycling center, fortunately the panel didn't get smashed (since they handle junk they don't take much care).
When connected to power it turns on, the backlight lights up but the display remains black. If I let it sit there for 10 seconds or so it goes in standby. I tried connecting both VGA and audio, the display remains on and I can hear the audio coming from the internal speaker.
After I popped the back cover open (which required removing a million screws) I got out the thermal camera and noticed that the TCON wasn't heating up. A quick check with the multimeter showed 0V on both sides of the fuse.
Looking at the main logic board, I found the circuit that turns on the voltage rail, the enable is missing.
Having nothing to loose, I cut the enable line and tied it to another “working” one. Now I have 12V to the TCON but the display is still black…
This is the first time I encounter this problem, I usually see the opposite: picture with no backlight.
I have a background in MacBook board repair, in that case a bad screen could also be caused by a bad/incompatible EDID firmware on the TCON's EEPROM. Could this be the case? The logic board does not like the display so it doesn't turn on.
Should I replace the TCON? Since I don't know what I'm going to do with It I want to keep the expenses to a minimum. If I can find the EEPROM's dump I may just replace that.
I Haven't tried poking the LVDS connector with an oscilloscope, but I'll do that as soon as I get some time to set it up.
Thanks!
This one got me stubbed, I found this NEC X551S Digital Signage display at my local recycling center, fortunately the panel didn't get smashed (since they handle junk they don't take much care).
When connected to power it turns on, the backlight lights up but the display remains black. If I let it sit there for 10 seconds or so it goes in standby. I tried connecting both VGA and audio, the display remains on and I can hear the audio coming from the internal speaker.
After I popped the back cover open (which required removing a million screws) I got out the thermal camera and noticed that the TCON wasn't heating up. A quick check with the multimeter showed 0V on both sides of the fuse.
Looking at the main logic board, I found the circuit that turns on the voltage rail, the enable is missing.
Having nothing to loose, I cut the enable line and tied it to another “working” one. Now I have 12V to the TCON but the display is still black…
This is the first time I encounter this problem, I usually see the opposite: picture with no backlight.
I have a background in MacBook board repair, in that case a bad screen could also be caused by a bad/incompatible EDID firmware on the TCON's EEPROM. Could this be the case? The logic board does not like the display so it doesn't turn on.
Should I replace the TCON? Since I don't know what I'm going to do with It I want to keep the expenses to a minimum. If I can find the EEPROM's dump I may just replace that.
I Haven't tried poking the LVDS connector with an oscilloscope, but I'll do that as soon as I get some time to set it up.
Thanks!
