CHGR_UGATE low voltage 820-2850

[appleonarim]

Hi everybody

I have 820-2850 board, its have PPBUS_G3H 2V. When i checked voltage CHGR_UGATE is 2V so Q7030 cant create PPBUS_G3H. ( When i inject 12.8 V PPBUS_G3H line machine is working )

Replaced 3 times U7000 ,q7030,q7035 ( same time replaced) . I cant find ISL6259AHRTZ datasheet for understand how is CHGR_UGATE creating, any idea about problem.

Thanks.

 

[aprendiz]

Check CHGR_DCIN, CHGR_RTS_L and CHGR_ACIN voltage and report values....

 

[appleonarim]

CHGR_DCIN is 16.5V
CHGR_RST_L is 3.38V
CHGR_ACIN is 3.99V

 

[dukefawks]

Check sense resistors R7021/22/51/52 and traces. If OK then remove F7040 and check again.

 

[appleonarim]

When measure r7021/22/51/52 its shows correct value. removed f7040 nothing changed. But problem interesting 5 seccond PPBUS_G3H is 14Volt and down 2Volt for 5-7 second then again 14V up down up down

 

[larossmann]

All my fucked up 2850s do that. What happens if you short the pins of the SMC data line talking to the U7000 together with a solder blob or tweezers momentarily, do you get 12.23v steady or still jumping?

 

[appleonarim]

Yes Louis when i put jumper U7000 10-11 pins PPBUS_G3H is ok ( first 13V then 11.9V ) machine starts. But i think cant see or charge battery? What is your suggestion? I have to Replace SMC?

 

[appleonarim]

When i changed 2 times SMC nothing change PPBUS_G3H voltage is low machine cannot turn on and battery is not charging. Any idea for next step?