820-4924-a j5250

[gadgetfix]

Hey all i got 820-4924

Previously water damage after wash everything working well, except when you close the lid the macbook apple light does not turn off and macbook does not sleep. So i opened her up to inspect around smc_lid_r and found few components are burnt out and corroded.

on the J5250 there is a small cap which was badly corroded. I looked on schematics and couldnt find the specifications on it. Does anyone know or can help me so I can replace it?

Thanks

 

[aprendiz]

Dont know but you can take it from donor board...

 

[Paul Daniels]

Got a photo of it? Does it work/behave if you don't have the cap there?

 

[Paul Daniels]

No Title

I wonder if that's the cap you're referring to? 1nF 50V 0402.

 

[gadgetfix]

Yeah, thats the one mate. I measured one from a working board which presented 100nF which would be 0.1uF? definately 0402 and no harm using 50v right?

 

[Paul Daniels]

Given that it looks like its primary purpose is just to be a noise squelch, you probably should be fine with anything from 1nF~100nF, though replacing it with 1nF 50V would be preferred of course since that's the original value.

I'd say the 100nF reading you got was because of the rest of the collective capacitance, between the traces/board-layers/connectors/pins. 50V rating might be simply because it was easier to utilise an existing value used elsewhere on the board, but certainly try stay with 1nF/50V if you can.

Does it work without it?

 

[gadgetfix]

jsut tried without. no sleep mode. i will try with 50v rating. c what happens. thanks paul

 

[gadgetfix]

yerp tried with 1nf 10% 50v not working. gunna look elsewhere

 

[Paul Daniels]

Guess you'll have to debug that net in more detail. Perhaps there's a continuity break to the SMC? What voltage do you get on SMC_LID when open, vs when closed?

What's the diode-mode value of the line? (red to ground).

 

[aprendiz]

Probably corrosion under LID board, do a continuity test...

 

[dukefawks]

Does SMC_LID go low when you hold a magnet over the Hall sensor?

 

[gadgetfix]

broken trace. fixed. i got the same issue on another a1502 however it is 820-3476A
My question is the resistor on the SMC_LID_R? can i bypass that? its only 0ohm? whats the point?

 

[dukefawks]

0 Ohm resistor can be jumped if it does not carry any current and is not meant as a fuse. In this case it is in a signal line so can be jumped. It may have been there for an R/C delay/filter that was scrapped after the board was finished.