820-000165 wont turn on

Kyle93

Active member
820-000165 with no liquid damage wont turn on. All power rails good up to P3V3S3 which is only 0.12V checked for shorts on both rails are not shorted. I see PM_SLP_S4_L is responsible for P3V3S3 I have 0V on PM_SLP_S4_L but no shorts on either rail.

What to check next???
 

Kyle93

Active member
When checking pin 9 of U7100 noticed it was worked on before and was only getting 0.34V so changed ISL but in process the board made a snap noise and I now have a short on PPBUS_G3H. With all caps and ISL removed the short still remains. Is this a internal short at this point from using to much heat?
 

Kyle93

Active member
with F1740 starts at 0.10ohm and continuous climes to a higher number 1 by 1 every few seconds

without 0.395

checked everything with F7140 removed and short doesn't appear anywhere anymore. As soon as F1740 is back on o.10ohm and climbing returns. Tried different fuse but same result
 

2informaticos

Administrator
Staff member
If you really have short on PPBUS_G3H, it MUST be present in one pad of F7140, once removed...
Disconnect charger and battery, when check diode mode, or ohm scale...
 

Kyle93

Active member
0.90 with F7140 and 0.390 with it removed. Assuming I don't have a short at all now.

What to check next? PPBUS_G3H only 0.272V already replaced ISL6259
 

2informaticos

Administrator
Staff member
F7140 has two pads.
So if removed, you MUST get two different readings; for each pad.
And you should get higher values without fuse; this depends by measuring pad too.
 

JohnB8812

New member
We asked resistance not diode mode. However, that is not good on pin 1 so you have a short on pin one side of PPBUS more than likely.
 

2informaticos

Administrator
Staff member
You do something wrong.
Cannot get lower reading without the fuse.
However, 135 (diode mode) is correct value.
No need to remove fuse then.
All I told to do is because you wrongly assumed a short there.

Be sure ISL6259 is properly soldered and post some voltages; 1, 2, 3, 9, 12, 13, 14, 17, 19, 20, 27.
 

Kyle93

Active member
Pin 3 had a short so replaced ISL6259 and afterwards was 0.10V on pin 3 but 5V on pad one on R7110 R7111 and C7111 for a short bit and now 0V again and short returned.

This is the 3rd ISL 6259 I have replaced on this board now.
 

Kyle93

Active member
replaced ISL6259 once again now 4.87V on R7110 R7111 and C7111 but only 0.15V on the actual pin 3 of the ISL. My soldering is fine and traces look fine, no liquid damage on this board.
 

Kyle93

Active member
Short again on ISL6259. What to check to see what keeps shorting it? Already replaced D7105 R7105 C7105 C7111 R7111 R7110 R7186 R7185 C7185
 

2informaticos

Administrator
Staff member
Please, specify where the short is; and post the ohm value.
You must get aprox 4V on ACIN pin of U7100.
Check the trace from pin3 to R7110/11; with multimeter, not the eye!
 

Kyle93

Active member
short was on pin 3 and 0.5 ohm

replaced Q7180 and ISL at same time and so far short has not returned.

Only 2.5v and fluctuates down to 0.500V and back to 2.5V on pin 3. Ran jumper to rule out trace issue

Also still only 17.5V on pad 2 of R7185 and C7185 but both have 18.5v on pad 1.

R7186 only 17.75V on pad 1 and 2
 
Top