"How Would you Probe?" Challenge:
I had a mains 120V hot wire for a light fixture arc to the house ground wire. Just a quick pop - nothing hurt but my pride. It threw the breaker. Perhaps coincidentally, a monitor on the same breaker circuit no longer worked. It wasn't on at the time, but it was working before, then it was dead.
By dead, I mean when you press the power button on the front, nothing happens. It has no lights when in the off state to let you see that there was at least power to an LED.
I pulled it all apart and did some probing. I "spray painted" key parts in a picture below for reference.
The brown board on the right is the DC power converter and screen back light power. It has a crapload of SMD parts on the back.
The green board in the middle is the monitor pixel data business end. It takes input DVI or VGI and processes it out the top to the monitor.
The green board on the left is independent of the problem I believe - it is USB and amp for speakers.
Here's what I found probing:
Yellow - there are four two pin wire-to-board connectors here . They connect to four cables on the monitor. I suspect they are backlight connectors. I read essentially 0 VDC on these. AC gave 1.8V. Is there such thing as a 1.8VAC backlight?
Red-on the very right is the cable for AC in (plug to the wall). I probe for ohms at the fuse immediately off of it and it showed good with a closed circuit (0 ohms). I didn't lift either leg on the fuse, though. Its a through-hole packaged fuse.
Red Circle At Top of Brown Board - this is a 6 pin connector labeled 5V, 5V, Gnd, Gnd, O/F, BK. Probing DC, the 5V's both showed about 5.2Vs. The BK showed a -0.6V to ground. I find that weird. O/F showed no DC voltage. This one plugs into the middle green board. Don't know what O/F or BK mean.
Blue connector - this goes to the monitor screen. It must be what tells it pixels info and to "turn on".
The ribbon cable on the left goes to the power and menu buttons.
At this point, I am uncertain as to which board would be the one to focus on. However, since I have 5V's coming out of the brown board, I feel I should next be probing on the middle green board.
Thoughts?
Thanks,
Sean
