Need to know VCC pin

[data-medics]

Hello, I'm trying to recover data urgently off of a Sandisk USB drive. The PCB has a crack in it near the port (no surprise). I was able to trace where all the connections go except for the VCC. It seems that it's not making it to the controller and it ducks under to a lower layer in the PCB where I can't visually trace it.

Here's a picture of the controller:

Can someone tell me where the VCC goes to on it? I know this may be a noob question, but I'm not typically a flash guy (usually I send the difficult ones out, but no time on this one).

[data-medics]

I know it's usually the bottom right corner, but I don't want to take a guess and be wrong..

[arvika]

Controller 20-82-00162-3 has VCC in this place (red mark). It should be same in 20-82-00162-2.

Attachments

[data-medics]

Ok, thanks a million. That's the one I though it was, but wanted to be sure.

Unfortunately even after powering there, I still get nothing from the thumb drive... I'm thinking that the PCB may have shorted the controller when it cracked and now it might be toast...

Any ideas?

[jermy]

nand Chip-off

[arvika]

@jermy: this controller crypt data so PCB must be repaired.
@data-medics: you must use microscope and verify the traces and controller pads. Sandisk sometimes has traces inside PCB and it could be quite problematic to regenerate but from my experience usually it is possible.

[jermy]

@jermy: this controller crypt data so PCB must be repaired.

yep, just noticed

[HaQue]

good news is that many Sandisk PCBs are exactly the same. If you swap controller and nand, and it is actually an electronic component that is the issue, you will be ok.

Havent tested it, but because there is no solution at this stage to the encryption, swapping just the NAND is actually worth it if the controller and pcb are exactly the same.

[arvika]

Brian, i test it many time. Not even one case work after swap

[data-medics]

Unfortunately, even with tapping in a completely new USB port I still can't get anything, not even a blink of the LED. The data channels were quite obvious and the ground was a cinch. Now I have the voltage to the VCC pin, but still nothing...

Sucks, too because these people are desperate.

[arvika]

Put here or send via PM high resolution scan (2400dpi) of flash - both side.

[enroute2]

arvika,

Would you be kind enough to give schematics or suggestions to fix traces on San Disk thumb drive?

Thank you kindly,

Jeff

[fzabkar]

Brian, i test it many time. Not even one case work after swap :(

Not even after swapping both controller and NAND?

[HaQue]

arvika,

Would you be kind enough to give schematics or suggestions to fix traces on San Disk thumb drive?

Thank you kindly,

Jeff

if you have a current case, then post pictures of it. If you are talking generally, then it is a case by case basis as rarely are any 2 cases the same. the idea of fixing traces on a Sandisk is the same as any other UFD.. investigate under a microscope and rectify any broken traces if possible, and/or do chip off recovery.

Flash drives are VERY touchy on how signals in traces affect each other. For example I have seen schematics that say "a 4 layer circuit board MUST be used" or "Traces should be xxx distance from each other, or not more than xxx length"

Also I believe firmware corruption happens on some cases when physically damaged. Fixing the traces doesn't always yield a result.

[arvika]

As Brian said, Sandisk flash PCB quite often have few layers of traces, even inside PCB. To repair it you must check damage under microscope, find where is broken and make shorting with thin wire.

@fzabkar: yes, both.

[HaQue]

further to this: we are getting monolith chips where the wire bonds inside the thing have come off. This is probably caused by user flexing it. In some cases the monolith is actually snapped in half. I believe the same thing can happen to the inside layers of regular PCB based Flash. Some SD Cards in particular have extremely thin PCBs.. as thin as paper

[jeremyb]

If the PCB is badly damaged swap the controller and NAND do a donor. As-long-as it's in the same series PCB you should be good.
Its pretty rare when I have to swap SanDisk PCB's, they are very repairable unless the end user really destroyed it.

Do you have a picture of the crack?