820-00165 fan spins once

ielectron

Member
was bit water damage around smc R5180 R5179 replaced, it was working for few days, now came back

-ultrasonic done, looks good actually

-green light is ok on cgarger
-fan spins once then dies
-r7121 r7122 are ok 10ohm, that area is not water damaged
- i can do smc reset
-it powers on on for a sec, aftger that i can start it again with the power button, but after 1 sec it goes down, and takes 0.34A
-when it powers on i can see 1.8V 1.05 5V, all of them, then the go away, but 8.59V 3.3V 3.4V remain, they are ok

-i replaced the bios from a donor board to see if it stays on but does the same, so i put back the original bios
 

ielectron

Member
yeah, in SMC bypass mode it turns on and there is picture

i will try to leave it overnight in full alcohol, maybe it can remove some crap under the smc, if that wont work i will reball it it, and have some donor board to replace SMC if needed to

thx!
 

ielectron

Member
i reballed the smc, then replaced it from donor board, same exact issue

powers on 0.5A, fan spins, than dies,

its not smc,
 

ielectron

Member
L5001 is corroded, that give 3.24V to SMC, there was no connection to C5001, i fixed it with a cable but still same, to measue if connects to under the smc i hav eto remove again the SMC.....
 

JohnB8812

New member
That's your problem then is 27/28. One of the the following is true:

1. R7121/2 is blown or both
2. R7120 is blown (possible but much less likely)
3. The traces from the ISL to R7121/2 are bad OR from R7121/2 to R7120 are bad.
 

ielectron

Member
22 hours ago
Check resistance between pìns 17/18 and 27/28 at U7100.
Also post voltage for pins 9 & 15.

so..

resistance between pìns 17/18 3.4ohm

resistance between pìns 27/28 174ohm

voltage for pins 9 & 15., both 0V


g3h is stable 8.58V, i have 3.3V 3.4V, green light on the charger
 

JohnB8812

New member
Yes your problem is pins 27/28 should be more like 21 ohms not 174 ohms. Check aforementioned resistors and traces.
 

ielectron

Member
i replaced r7121, now its 10 ohm both resistors, but same issue

also i checked them before, even in the original post i mentioned them, they were both good, r7121 burnt later during diagnosis
 
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