SanDisk SSD 120GB doesn't power up

[amaliagr]

Hello,

I have a Sandisk SSD 120GB, model: SDSSDA-120G, that doesn't power up and doesn't show up in any system. I tried to compare it with another identical drive that i have and do some measurements with a multimeter, but since i do not really know what to look for, i couldn't figure out the problem. I noticed that the voltage that comes from the psu port is correct for the +12V and the +5V, but the +3.3V appears to be ~0.35V. I suppose, since this does not happen with other drives on the same psu, it is probably caused by a shortcircuit on the drive, but i do not have the skills to locate it I have attached photos of the SSD. Any help will be really appreciated!

Thank you in advance!

Attachments

[Lardman]

Start by checking the 0 ohm resistors for continuity.

Then each of the rails at the PMIC for resistance to ground (use a screwhole) It looks a little discoloured around that area - anything getting hot?

[amaliagr]

Thank you very much for your reply!

I am not really experienced in electronics, so i need some clarifications

First i should measure the resistance of the resistors (black chips named RXX) and make sure all of them have a value and not infinite, correct?

You lost me completely about the PMIC chip.

Nothing gets too hot, i checked.

Thank you for your patience!

[fzabkar]

Measure the voltages at V1, V2, V3. Use a screw hole as your ground reference.

If all voltages are OK, short the ROM mode pads with tweezers while powering on the drive, then release the short. The SSD should then identify itself with its factory alias.

Attachments

[amaliagr]

Hello,

Thank you for your reply!

For the faulty drive i get the following measurements at the inductors:
V1: 0.00V - 0.01V
V2: 0.13V - 0.24V (going up and down in this range)
V3: 0.94V - 1V (going up and down in this range)

For the healthy drive i get the following measurements at the inductors:
V1: 3.3V
V2: 1.2V
V3: 1.8V

Shorting the ROM pads didn't change anything, drive doesn't id.

Thank you again!

[fzabkar]

Did you start with @Lardman's instructions? That is, measure the resistances between ground and V1, V2, V3. Also check the two resistors marked "0".

[amaliagr]

Hello,

i set the multimeter at the 20k scale and with the drive not powered i measure the resistance:
between ground and V1: 8.5kOhm
between ground and V2: 1.33kOhm
between ground and V3: 11.9kOhm

The two zero ohm resistors seem ok, i measure ~0 ohm.

Thank you!

[Lardman]

There's a 5v VCC test pad on the controller side of the pcb just above R100 check to see if you have vcc present at it. Looking like a dead pmic to me.

[fzabkar]

I noticed that the voltage that comes from the psu port is correct for the +12V and the +5V, but the +3.3V appears to be ~0.35V. I suppose, since this does not happen with other drives on the same psu...

The 3.3V power pins have been redefined. Pin #3 is now the Power Disable pin. Some drives support this pin while others do not.

3.3V -> power disabled
0V -> power enabled

[amaliagr]

There's a 5v VCC test pad on the controller side of the pcb just above R100 check to see if you have vcc present at it. Looking like a dead pmic to me.

Yes, i measure 4.75V at the test point.

[amaliagr]

I noticed that the voltage that comes from the psu port is correct for the +12V and the +5V, but the +3.3V appears to be ~0.35V. I suppose, since this does not happen with other drives on the same psu...

The 3.3V power pins have been redefined. Pin #3 is now the Power Disable pin. Some drives support this pin while others do not.

3.3V -> power disabled
0V -> power enabled

I measured the sata power connector pins:
P1: 0.17V - 0.4V (going up and down periodically in this range)
P2: 0.17V - 0.4V (going up and down periodically in this range)
P3: 0.17V - 0.4V (going up and down periodically in this range)
P4: 0V
P5: 0V
P6: 0V
P7: 4.96V
P8: 4.96V
P9: 4.96V
P10: 0V
P11: 0V
P12: 0V
P13: 12V
P14: 12V
P15: 12V

[Lardman]

If you have VVC at the test point and no other voltages I'd pull the PMIC and check for VCC at it's pads.