A2141 - 820-02037-A - liquid - 20V 0,4 Amp. No short to SSD

[samstown]

Hello

I know this model is fragile and most of the time SSD are dead. I want to make sure I correct information to the customer.


no usb activity
PPVBAT_G3H_CHGR_REG 12.59V
PP2V5_NAND_SSD1 2.53V (no short between 12V and 2,5 V)

Near U7800
PP1V2_Awake 1.2V on C7914
PP3V0_G3H_RTC 3V on C7906
PP0V8_SLPS2R 0.8V on C7905
PPVDDCPU_AWAKE 0.92 on C7827
P1V1SLPDDR_RAMP 0.92V C7920

Near U7650
PP5V_S5_LDO switch between 0-07 V


To test DFU before trying on that faulty motherboard, I have a working board, I am trying to put it in DFU using Force DFU with a swtich but it doesn't work.

1. Connect power cable and DFU cable.
2. To avoid any weird symptom, force the machine off, pressing power button 5-8 seconds.
3. Press FORCE_DFU switch for 3-5 seconds; you should see DFU logo now.

Thanks
Sam

 

[samstown]

ok, I got the right way to access DFU with the switch. It's working on both motherboard (Bad and good).

1. Connect only power USB-C on DFU Mother board
2. Open AC2
3. Press the switch and hold it
4. connect thunderbolt USB-C to USB-C to AC2 Intel Macbook
5. DFU should appear

Now I'll try a revive on the bad one.

 

[samstown]

Anything to do ?

 

[2informaticos]

Do you get all SSD0 and SSD1 voltages?

 

[samstown]

Now that I did try "revive" it take max 0,1 amp, it's no longer going up to 0.4amp

I am not too sure which SSD voltage I need to check

HS_P3V3_G3W_SSD0_OUT = 0.06V
HS_PBUS_MAIN_SSD0 = 0.22 V
P1V8_LX0_SSD0 = 0V


HS_P3V3_G3W_SSD1_OUT = 0.06V
HS_PBUS_MAIN_SSD1 = 0.22 V
P1V8_LX0_SSD0 = 0V

 

[2informaticos]

I suppose you are using 01700 schematic, as 02037 isn't available.
SSD0/1 voltages are available on pages 92 & 87.

 

[samstown]

Correct, I use 01700 and board is not same on SSD area. I see those SSD power line on schematic but when I look at boardview, it's not same.
PP0V9_NAND0
PP1V2_NAND0
PP2V5_NAND0

PP0V9_NAND1
PP1V2_NAND1
PP2V5_NAND1
I don't know if the pics can help. The flapping between 3,3 to 1,55 mean something?

 

[2informaticos]

One bad NAND can cause such fluctuation.

Checked these too?
Some coils may be on the opposite side also.

 

[samstown]

thanks. 0V on the one you highligthed. I don't have an exact same board to compare. I have a 820-01700 working.

 

[2informaticos]

"0V on the one you highligthed"
What about diode mode?

 

[samstown]

"0V on the one you highligthed"
What about diode mode?

.359
.409
.409

 

[2informaticos]

Can you still access DFU?

Revive not always help.
Restore is better, but will erase SSD; if completes successfully.

 

[samstown]

I can try again revive, you think I should ? I need the data

 

[samstown]

I can put it on DFU only when connected to left side. When I try from right USB-C it doesn't work. I guess it's normal. Revive keep giving same error

 

[2informaticos]

There is a dedicated DFU port (only one), left back.

Your problem may be SSD itself; usual for sudden death.
Restore will fail too, in such case.
And data can't be recovered...

 

[samstown]

looking with thermal camera I see heartbeat on TPS51980B (U7650). is the chip faulty or something making the hearbeat happening ?
I've checked all components around and couldn't find anyhting wrong. I'll keep searching.

 

[2informaticos]

Any voltage pulse at L7600/60?
Check diode mode to ground on all big coils.

 

[samstown]

yes, L7600 0,5v to 2V (diode mode .032) and L7660 1V to 3,3 V (diode mode .330)
L7211 and L7221 = .006 that's not good, isn't it ?

 

[2informaticos]

"L7211 and L7221 = .006"
Looks good for CPU power core rail.

"L7600 0,5v to 2V (diode mode .032)"
This doesn't look good; 0.032 is too low there...

 

[samstown]

so L7600 is is PP3V3_G3_H_T. This one is the frist one we need to boot, right ?