J8300
P1: 0V

U7701:
P5: 5V
P18: 5V
P17: 3.3V
P11: 12.42V

Q7706
P1,2,5,6: 0V
P3: 12.5V...

2informaticos Got a known good... still has image, but no bklt... :-?...

Resistance to ground at pin 1 is 1.23 with screen unplugged. 0 with screen plugged in (suggest short in screen?)
Continuity from pin 1 to D7701-...

Resistance to ground at pin 1 is 1.23 with screen unplugged. 0 with screen plugged in (suggest short in screen?)
Continuity from pin 1 to D7701-...

I will check. My other question is, is there a way to reliably test a screen backlight without getting a new one? I am out of known good, am at a down...

Have a late 13 3662 with no back light and MagSafe stays orange (no charge in battery) history is that water from a faucet dropped on Apple logo over...

No pulse of any kind. I also checked for shorts... on 18,19 and 3,4 with RTG of .6...

You can make this "solved"

Missing BKLT and IMAGE- Affirmative
No chime
Yes USB Activity
0 volts anywhere on J8300.
No external display either.