820-2530 No Power

Bouba148

New member
Doesn't turn ON, No green Light, No water Damage

at U7000
1: CHGR_AGATE 14.5V
2: CHGR_DCIN 0V

Replaced D7010 and U7000 (ISL6258)

Then my DC power supply went in Protection because of a short to gnd: CHGR_DCIN : 3V
C7020 burning hot
Replaced C7020:
PPBUS: 12.60 V
PP3V42_G3H: 3.408V but still no green light

S5 State ok
PP3V3_S5: 3.322v

Checked R17/18 and R27/28 :
R17/18: 20.8 Ohms
R27/28: 1.7 KOhms both R7021 and R7023 bad
Replaced both R7021 and R7023 R27/28: 20.6Ohms

Still not turning ON when shorting R5015 or R5016
But Turning ON in SMC bypass mode.

CHGR_ACOK: 3.274V

Activity OK on Both SMBUS_CHGR_SCL and SMBUS_CHGR_SDA: SMC talking to ISL : pulses on scope
SMC_RESET_L: 3.405V and pusing to gnd when shorting R5015: OK

Resistance to ground on PP3V42 : 5.4 KOhm

Bad MCP I guess, please confirm as I don't want to waist my time ( and yours ) on that historical board.....
 

2informaticos

Administrator
Staff member
"But Turning ON in SMC bypass mode."
You seem to be lucky guy.
5.4K on 3V42 usually points to bad MCP; but not 100%, like in this case.
However such low value denotes it is on end life...

Post voltage for pins 9 & 15 of U7000.
 

2informaticos

Administrator
Staff member
Yes, but still has one sensor which blocks the SMC.
First check if AVREF_SMC is OK.
If yes, check all VSENSE outputs from page 44.
 

Bouba148

New member
PP3V3_S5_AVREF_SMC: 3.298V, OK

SMC_CPU_VSENSE: 0V
SMC_MCP_VSENSE: 0V
SMC_PBUS_VSENSE: 0V

Those Vsense signal should be High or Low?

By the way how are you? long time no see......and thanks for replying my friend
 

Bouba148

New member
SMC_MCP_CORE_ISENSE : 0V
SMC_MCP_DDR_ISENSE : 0v
SMC_CPU_FSB_ISENSE : 0V
SMC_CPU_ISENSE :0v
SMC_BATT_ISENSE : 0V
SMC_DCIN_ISENSE: 0V

In SMC Bypass mode:
SMC_MCP_CORE_ISENSE: 1.173V
SMC_MCP_DDR_ISENSE: 0.403V
SMC_CPU_FSB_ISENSE:0.811V
SMC_CPU_ISENSE: 0.492V
SMC_BATT_ISENSE 0.042V
SMC_DCIN_ISENSE: 0V
 

Bouba148

New member
Hi 2Informaticos,
I'm back with that board and I'm very surprised that it's turning ON when I short the power pads now.......why????? ni idea
Just Noticed that the Fan spins at full speed, I will reassemble it and run the corresponding ASD to check if any sensor is alarming..........except if you advise me to test something else before........
 
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