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3332 PPBUS 12.65V no fan spin

G

grmacs

Member
Liquid damage residue around U7201 U7600, U2600 inside edge of SMC (cleaned up and reflowed).. U7201 was where there was noticeable corrosion.

Definitely was missing some voltages at U7201 and replaced it got some of those back but
pin 13 and 22 are both 1.3V I'm thinking those are both supposed to be 5V? If so not seeing short at least.
Pin 13 diode red to ground .519V and 22 is .565V
PM SLP S5L at dead 0V.
 
2informaticos

2informaticos

Administrator
Staff member
Then you must get 2V at pin 13, 3V3 at 22 and 5V at 29.
If not, change U7201.
Be sure no short on any of mentioned pins; also check at L7220/60.
 
G

grmacs

Member
Had .12V drop reading on L7260.
Have .08V voltage drop on pin 2 of L7260 after pulling it. Safe to inject V on pin 2?

No change in voltage readings at U7201 after pulling L7260... not sure if that would imply I also to change U7201. SOlders look very good around it. Diode red probe to ground at U7201 pins below looks good:
13, 22 & 29 all between .490V and .570V
 
G

grmacs

Member
I think it was soldered correctly but I then definitely caused a short that burned up q7260 and now short on pin 2 of L7260 with q7260 removed!
Anything I can do other than inject voltage?
 
2informaticos

2informaticos

Administrator
Staff member
Start with 1V and go up to 4V, no more.
Depends of the ohm value to ground.
With 80 ohms, maybe nothing gets hot.
Still have the chance some chip enters in thermal avalanche...
 
Last edited:
G

grmacs

Member
This board is trashed. Q7630 burned up and near 0v diode drop on multiple rails including .04V drop on pp1v05 S0 with R7640 removed. I'm assuming bigger damage done.
 
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