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820-01041: No powering up

M

macRepairAmb

Member
Got another 820-01041 board that's not powering up. Initially, PP20V was 5v. Replaced UB300, which had a blowout on the surface. Once replaced, 20V was back. With the board back in the system, every few minutes or when I press the power Botton, the fan would spin up for about a second before it shuts off. I can also see a quick spike in current draw before it drops out. Here are the readings I have so far

PPBUS_HS_CPU - 12.6
PPBUS_HS_GPU - 12.6
PPBUS_HS_OTH5V - 12.6
PPBUS_HS_3V3G3H_T - 12.6
PPBUS_HS_3V3G3HRTC_X - 12.6

PP5V_G3S - 5.1
PP3V3_G3H_T - 3.3
PP3V3_G3H_RTC_X - 3.3
PP3V3_G3S_T - 3.3

PP5V_S4_T_USBC - 0 (does not spike up when there board does draw current for a second)
UPC_T_5V_EN_R - 0 (does not spike up when there board does draw current for a second)


PM_RSMRST_L goes to 3.4v for 10 seconds after 20v power kicks on then turns off after 5 seconds.
UPC_T_5V_EN stays low the whole time

SMC_PCH_PWROK - also spikes to 1.79 but drops out within less than a second.
Same with SMC_PCH_SYS_PWROK, SMC_SYSRST_L.
SMC_RSMRST_L stays at 1.79 for about 4 to 5 second before it drops out.

PPVCCIO_S0_CPU - 0.9 during the current draw and drops to zero within a 2 seconds
PPVCC_S0_CPU - 1 during current draw and drops to zero within a 2 seconds

What else should I check or any suggestions
 
2informaticos

2informaticos

Administrator
Staff member
Test the board alone, no power button connected.
The board should start automatically, when charger is connected (battery removed).
For debugging, use SWK000/002 instead power button, to check signals reaction triggering PMU_ONOFF_L.

"SMC_RSMRST_L stays at 1.79 for about 4 to 5"
Do you get PP1V8_SLPS2R?
If yes, check if PM_RSMRST_L goes high at same time.

Check if PM_PWRBTN_L reacts (drop pulse) triggering PMU_ONOFF_L.
If yes, check for reaction at all PM_SLP_Sx_L lines.
If not, check PCH_BATLOW_L level.
 
M

macRepairAmb

Member
PMU_ONOFF_L - 3.38. Drops to zero when SWK000 bridged.

PP1V8_SLPS2R - 1.8 the whole time. Stays on from when the power is plugged to the board with PP20V @ 5v to when 20v is switch on. Never drops.

PM_RSMRST_L - 3.3 for about 5seconds before it drops. Also, it only goes high once the board starts to pull current, which is about 10sec after 20v becomes active to board is active.When I trigger PMU_ONOFF_L, it goes to 3.3 again for 5 seconds.

When PMU_ONOFF_L is triggered, PM_PWRBTN_L goes to 3.3 for about 10sec before it drops

PM_SLP_S0_L - 1.8 for about 5 sec
PM_SLP_S3_L, PM_SLP_S4_L, PM_SLP_S5_L - 3.3 for about 2 sec

Also checked, PCH_BATLOW_L which reacts the same 3.3 for about 5 sec.
 
M

macRepairAmb

Member
I'm assuming I'll be using the PMU_ONOFF_L.

Still does the same current draw for a few seconds then back to 0A draw.

I did notice that CHGR_LX2 - voltage is all over the place, between 3.3v and 12v

Since I didn't have a similar board to compare to, I used 820-00840 circuit, which was similar to an extent. TBA_LX2 was constant at 13v.
 
Last edited:
2informaticos

2informaticos

Administrator
Staff member
"When PMU_ONOFF_L is triggered, PM_PWRBTN_L goes to 3.3 for about 10sec before it drops"
PM_PWRBTN_L reacts (drop pulse) if you trigger PMU_ONOFF_L in these 10s?
 
2informaticos

2informaticos

Administrator
Staff member
"PM_SLP_S3_L, PM_SLP_S4_L, PM_SLP_S5_L - 3.3 for about 2 sec"
Each of them enables a sleep state; something like Sx --> (Sx-1).
Check S4/3/0 voltages in these 2 seconds.
 
M

macRepairAmb

Member
PP5V_S4_T_USBC - never triggers. So check UPC_T_5V_EN_R, this too never triggers. On UB740, only PM_RSMRST_L triggers 3.3v for about 5sec. UPC_T_5V_EN never turns on. Wondering if i should change out the USBC chip that i had replaced.

Same readings on X line.
 
M

macRepairAmb

Member
Replaced the chip again with the same result. S4 still isn't coming on. Regarding your last post, unlike previous version boards, A1502 for example, the power Power Alias pages doesn't calls out S3 and S0 lines.
Here are the readings i collected:

PPVCC_S0_CPU - 0.995 for about 2 sec (schematic calls for 1.52v)
PPVCCSA_S0_CPU - 1.044 for 2 sec (schematic calls for 1.52v)
PPVCCGT_S0_CPU - 0.0
PPVCCIO_S0_CPU - 0.94 for 2 sec
PP1V2_S3 - 1.2 2 sec
PP1V2_S3_CPUDDR - 1.2 2 sec
PP1V2_S0SW - 1.2 2 sec
PP1V05_PRIM - 1.05 for 5 sec
PP1V05_S3 - 0
PP1V05_S0SW 1.04 2 sec
PPVCORE_S0_GPU - 0
PP3V3_S0_GPU - 3.3 2 sec
PP1V8_G3S 1.8 the whole time
PP5V_G3S - 5.1 the whole time
PP3V3_G3H_T - 3.4 the whole time
PP3V3_G3H_RTC_X - 3.4 the whole time
PP3V3_G3S_T - 3.3 the whole time
PP3V3_G3S_X - 3.4 the whole time
PP3V3_G3H_SOCPMU - 3.3 the whole time
PP3V3_G3SSW_SNS - 3.3 2 sec
PPVCCPRIMCORE_PRIM_REG - 1.05 5 sec
PP3V3_G3H_DFR - 3.3 the whole time
PP3V3_G3H_SSD0_SNS - 3.3 the whole time
PPBUS_G3H_SSD0_SNS - 12.5
 
2informaticos

2informaticos

Administrator
Staff member
"PP1V05_S3 - 0"
Check diode mode there.
This voltage must appear before 1V05_S0SW...

"PPVCCGT_S0_CPU - 0.0"
iGPU power stays at 0V untill open graphics application on iGPU, like YouTube playing...
Board starts with dGPU normally.

BTW, CPU voltages are dinamycally adjusted, as seen on the power supplies pages, not in power aliases one.
 
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