820-2936 green light fan spins and stops

[arnonabuurs]

After connecting the charger I get a green light no orange, the fan starts to spin for a number of seconds and then reboots. PPBUS goes to 12.58 then drops to 4v and shows OL, and then reboots. It cannot run only from battery. Onewire lines are all OK and3.42 is present. CPU Vcore comes on to 1.15 with fan spin. What to check next?

Some measurements

U7000 17/18 = 55.2ohm
U7000 27/28 = 21 ohm
ACOK = present on pin 14.
Pin 3 ACIN = 3.9
Pin 2 DCIN = 16.58 - 16.16v

 

[JohnB8812]

Pin 17 and 18 is your problem should be 3.9 ohms not 55. One of 4 things is true (or multiple)
1. R7051 is blown
2. R7052 is blown
3. R7050 is blown (much less likely but possible)
4. The traces between the ISL and R7051/2 are blown and/or the traces between R7050 and R7051/2 are blown.

 

[arnonabuurs]

Tanks John, havent been at it for a week but tomorrow will check these issues.