820-3536-a wont turn on

[Gannons3]

pin 12 is putting out 32.77khz

 

[dukefawks]

Check with the scope on L7520 if there is power pulses. Multimeter may be too slow to catch it.

 

[Gannons3]

is there any way i can check without an oscilloscope? i dont have one

 

[dukefawks]

Uhm, how do you know the 32kHz then? Most multimeters will get the short burst, but the auto ranging ones usually don't, is yours auto ranging?

 

[Gannons3]

I used the frequency setting on my multi meter and thats what it said; it is auto ranging

 

[Gannons3]

I do have a multi meter without auto ranging, ill try to find it

 

[Gannons3]

I still get a flat 0

 

[dukefawks]

Voltage on C1300/03? ADAPTER_EN, DSW_PWRGD?

 

[Gannons3]

3.35v on c1300 and C1303, 3.39v on adapter_en; and 3.42v on dsw_pwrgd

 

[dukefawks]

Well, I'm running out out ideas here. If there is no short on L7520 to GND it should power up and pulse at least. Could be corrosion under SMC or a dead CPU at this point.

 

[Gannons3]

how is pp5v_s4 created?

 

[dukefawks]

From the CPU/PCH in combo with SMC.

 

[Gannons3]

so the boards probably toast then, there wasnt any corrosion around the smc but there was some close to the cpu, Im guessing its probably toast, there was no short to ground on L7560

 

[dukefawks]

I'm out of ideas really. Inspect closely for corrosion, that is about all there is left to do. Reflow SMC/CPU if you are really desperate.

 

[Gannons3]

any specific lines i should be looking for corrosion on? other than pp5v_s4?

 

[dukefawks]

Anything around CPU/SMC/U6100/clock

 

[Gannons3]

If U6100 died could that leave me with no pp5v_s4? Because i know U6100 was corroded a little when i first opened it up

 

[dukefawks]

I doubt the chip is dead. Usually the traces or resistors are corroded. Yes without a functioning U6100 the board will power cycle. Pull U6100 and read it on the programmer, do not loose the original dump!

 

[Gannons3]

R6131 gives me 89.7k ohms and is supposed to be 33

 

[Gannons3]

theres nothing on the board there but its not labled no stuff on the schematic