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 some time. Display works fine, backlight does not. pin 1 at lcd bkltboost registered 0v. No real corrosion on board. Do you think it could simply be the screen itself even with 0v at lcd bklt s0? Do you think the no chargen is somehow related? I already checked/replaced lcd bklt chips. Ideas?
-
For $29/mo, we provide access to advanced level technicians who will answer your questions on any Macbook board related matter to the best of their knowledge promptly & walk you through how to solve your problem so you can deliver a working board to your customer.Subscribe Now
Late 13 3662 no bklt
- Thread starter Rford
- Start date
First check resistance to ground (diode mode, red probe to ground) at pin1 /J8300.
Also check if same pin has conitnuity to pin K/D7701.
Did you check F7700?
Post some voltages and signals for U7701, pins 5, 18, 17, 11.
Also check if same pin has conitnuity to pin K/D7701.
Did you check F7700?
Post some voltages and signals for U7701, pins 5, 18, 17, 11.
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 point in cash flow so can?t buy a known good and cant afford to take the hit of buying a new one if it?s indeed not the problem.
Some measurments can help you to discard between MLB and LCD assembly; but not always possible 100%.
You need to have at least a broken screen, with good backlight.
Better if you can get some areas with image on it.
You need to have at least a broken screen, with good backlight.
Better if you can get some areas with image on it.
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- Yes
F7700- good voltage to both sides
U7701:
Pin 5: 5.03V
Pin 18: 5.03V
Pin 17: 3.3V
Pin 11: 12.5V
Think the resistance to ground with the screen plugged in vs unplugged, plus good voltages suggests bad screen?
Continuity from pin 1 to D7701- Yes
F7700- good voltage to both sides
U7701:
Pin 5: 5.03V
Pin 18: 5.03V
Pin 17: 3.3V
Pin 11: 12.5V
Think the resistance to ground with the screen plugged in vs unplugged, plus good voltages suggests bad screen?
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- Yes
F7700- good voltage to both sides
U7701:
Pin 5: 5.03V
Pin 18: 5.03V
Pin 17: 3.3V
Pin 11: 12.5V
Think the resistance to ground with the screen plugged in vs unplugged, plus good voltages suggests bad screen?
Continuity from pin 1 to D7701- Yes
F7700- good voltage to both sides
U7701:
Pin 5: 5.03V
Pin 18: 5.03V
Pin 17: 3.3V
Pin 11: 12.5V
Think the resistance to ground with the screen plugged in vs unplugged, plus good voltages suggests bad screen?
You get short on backlight rail only when screen is plugged.
So bad screen, or video cable.
You must try other LCD assembly.
Look at the LCD connector.
An internal damage can cause a short even when good screen is connected (less probably).
So bad screen, or video cable.
You must try other LCD assembly.
Look at the LCD connector.
An internal damage can cause a short even when good screen is connected (less probably).
2informaticos Got a known good... still has image, but no bklt... :-?
Start posting voltages again with that screen.
J8300, U7701, Q7706...
J8300, U7701, Q7706...
Are you using original 85W Magsafe 2 charger?
Check SMC_LID signal.
Check SMC_LID signal.