820-00165

[Neil250]

No green light, no fan spin.
New flex cable tried and no go.
U7090 looks terrible. See image below.
PP3V42_G3H is 0V needless to say

0V at L7095

Tons of corrosion at U7090.
I don't like to just throw a board into a US cleaner but I am considering doing so on this one.
I can't even measure voltages at U7090 as pins 5-8 look like crap.
R7012 has 14.95-15.02 V





I have been away from repair from 3 months so I am a bit rusty.

 

[2informaticos]

Remove U7090 and resolder its pads, as on the board too; may need new chip.
Replace corroded components and rebuild traces, if necessary.
I don't recommend UC, if no other areas affected; scrub locally with alcohol and toothbrush.

 

[Neil250]

OK, replaced U7090
Rebuilt traces

Now I shifted focus to Q7010
PIN 5: 15.10
PIN 4: 14.9

The gate is way too high.
R7010 and R7011 are correct ohms
R7012 is correct

Could this be D7012?

 

[2informaticos]

Change D7012...

 

[Neil250]

replaced D7012.
Now have green light.
No fan spin

PPBUS_G3H now at 8.60V

USB PORT is working.

U7400 PIN 12: PP5V_S5: 1.22V
DIODE MODE, pin 12 here is 0.447V

 

[2informaticos]

"USB PORT is working"
I doubt, if you don't get RAM voltage.
Read "HOW TO collection" thread about how to confirm USB activity.

"PP5V_S5: 1.22V"
You shouldn't have 3V3_S5 in this case.
Post basic U7501 voltages; pins 23, 12, 13, 22, 29, 21.
Also check diode mode to ground at pins 22, 29 and L7520/60.

 

[Neil250]

U7560

6,7,8: 0 V
1: 8.60V



U7501
4: 0 V
12: 3.40
13: 0
21: 3.39
22: 0
23: 1.07
25: 0.62 V
26: 1.06
29: 1.23

DIODE
22: .55V
29: 0.45V

L7520: .426V
L7560: 0.36V

NOTICED
C7581 and C7583 missing endcaps
replaced them
FAN SPIN!!

 

[2informaticos]

" PPBUS_G3H now at 8.60V
---------------
23: 1.07"
Fix this problem...