820-00239 PP5VS4 Short

[goldcoastmick]

Hey guys.

13" 2017 4 port, powering on and stuck at Apple logo on first inspection.

Discovered customer severed trackpad cable while attempting DIY battery replacement WITH BATTERY CONNECTED and fried L4500 (charcoal!).

Full short to ground on PP5VS4. I removed L4500 and cleaned/dug around the roasted section and all layers seem to be clean and seperate so I suspect the short is somewhere else.

Any suggestions on a likely culprit on this rail, any "usual suspects"?

Just thought I'd ask before I inject voltage on the line since Banjo (u7800) is on this rail and I don't want to fry him...

Cheers,

Mick

 

[2informaticos]

So the short remains on pad 2 of L4500?
Very likely short between copper layers, underneath the pad.
Polish the edges of the hole, to eliminate any contact between layers.
You may need to dig a bit inside the board.

 

[goldcoastmick]

So the short remains on pad 2 of L4500?
Very likely short between copper layers, underneath the pad.
Polish the edges of the hole, to eliminate any contact between layers.
You may need to dig a bit inside the board.

Yes correct, the short remains on pad 2.

I will try a cleaning up the hole little more. What technique/tool do you use to "polish" the edges as you put it?

 

[2informaticos]

Fiberglass pen is very usefull in such case.

Any reason to quote an entire post visible few centimeters above?
Please, maintain forum aesthetic.

 

[goldcoastmick]

No reason in particular... Thats just what happens when you click the reply button apparently...

 

[2informaticos]

Yeah, no need to click it.
Just write on bellow empty box...