Can't read ROM On 771961

[samstown]

Hello,

I got WD 1TB that does nothing when USB plugged in. I tried to back up the ROM with PC-3000, I got UART, SOC but no ROM. If I try to backup another PCB, it works.
I don't have history of this drive and as far as I can see ROM looks ok.

I tried with CH341A programmer, it's not detected. I tried other, they are detected without problem

The ROM indication are

2SU20A
PJCV

Is there anything else I could try ?

Thanks
Sam

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[michael chiklis]

Usually when rom can't be detect is due short on 5V line.
If is a short issue (which would explain why the drive doesn't power on) then you could read rom content by unsoldering the chip and using your external programmer with SOP8 to DIP adapter.

[fzabkar]

The CH341 programmer is a 3.3V device. It can damage your circuit if any component on this supply rail cannot tolerate this voltage.

Can you measure the voltage between Vcc and ground of U12?

[samstown]

Thank you guys for your reply.

So If measure voltage between Vcc and GND I get 2.5 V.

[fzabkar]

So If measure voltage between Vcc and GND I get 2.5 V.

That's why you should avoid the CH341A programmer for in-circuit work.

[samstown]

So If measure voltage between Vcc and GND I get 2.5 V.

That's why you should avoid the CH341A programmer for in-circuit work.

So should I try to unsold ROM and use SOP8 reader ?