missing PM_SLP_S5_L on a 820-4924a

[Nick]

R1548 ok
R1549 ok

 

[Nick]

reflowed both U6101 and U1950 no change, still no 24mhz on Y1915

 

[Nick]

well it goes to 24mhz only on on buton press or magsafe plug in. for an instant

 

[2informaticos]

So 24MHz is OK.
For some reason board turns off and oscillation disappears too.

See if pins 2, 5, 6 of U6100 react when press power button.
Maybe need to remove J6100; sometime gets invisible corrosion under...

 

[Nick]

r1632 is 100k off circuit (like schematics) but on circuit it drop to 5k.
bad u6101?

 

[Nick]

pin 2 5 6 do the following at on button press/ magasafe in

0 v

rubbish oscillation

0 v

quick constant oscillation

0v

3.3v fixed no oscillation

it is very very very sudden

 

[Nick]

actually only 5 and 6 get that quick oscillation. 2 goes directly to 3.3v

 

[Nick]

removed u6101 but r1632 remains (on the circuit) at 5k

 

[2informaticos]

Did you remove J6100?

 

[Nick]

yes of course. first thing i did

 

[2informaticos]

Let see if starts in SMC bypass mode...

 

[Nick]

i tried earlier... no change... gonna try again in a second. so frustrating

 

[Nick]

Nope same stuff only thing that changes is the one wire led not turning on but that is normal

 

[2informaticos]

Check for short on any power rails; not only big coils.
Pay atention to Power FETs, at page 63; all these voltages should try to appear.

 

[Nick]

fun. ok getting on this now. it is the last one of this batch.. hopefully i get it working. i contacted the guy who previusly atempted to fix it. he said the only thing he tried to do was injecting around 5 v into L7520 but i doubt this caused any damage

 

[Nick]

u8000

u8010

U8030

U8050



u8020

U8070

u8060

u8080

U8005



all have no shorted output ;(

 

[2informaticos]

Can you see pulsing any of these outputs?
Maybe one has missing enable control...