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CompactFlash, SD, MMC, USB flash storage. Anything that does not have moving parts inside.
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2 diode burnt?

May 31st, 2011, 17:22

from this 1 gb pen drive there was a burnt strong smell.
i opened and i found the (diode?) burnt
a) C14
b) no text but it's possible to see from the pictures.

Any idea if both are simple diode?
DSC_0165.JPG
DSC_0166.JPG

Re: 2 diode burnt?

May 31st, 2011, 17:50

you can try and buy an identical one and try swapping the bad diodes (assuming that no other diode/resistor is bad), or you can send to a professional. a professional will probably only charge 200-300 to extract the data from the chip manually.

Re: 2 diode burnt?

May 31st, 2011, 17:53

hi - did u try to enlarge the pictures, are u sure they are just diode ?
it's a no-name pen drive so i would like to shortcut them (assuming that a bad usb port made this burn - and that they are diode)

Re: 2 diode burnt?

May 31st, 2011, 18:07

positivebit wrote:i opened and i found the (diode?) burnt
a) C14

Hint - a diode PCB marking would not start with "C" :)

positivebit wrote:b) no text but it's possible to see from the pictures.

I would trace the PCB tracks to identify the likely function of that component - but it looks the same type as "C14".

positivebit wrote:Any idea if both are simple diode?

Not diodes - at least not "C14"; I would need to spend more time tracing the PCB to check the other burned component. Do NOT short-circuit them, as you suggest later.

What does the customer say was the cause - was there a possible overvoltage?

Re: 2 diode burnt?

May 31st, 2011, 23:19

I agree with Vulcan regarding the circuit tracing.

Usually when an electrolytic capacitor fails catastrophically, the cause is an overvoltage, or reverse polarity. There appears to be a 3.3V linear regulator (U6) between the USB port and the controller and flash memory. Hopefully it will have limited the damage. I can't read its markings, but a typical pinout would be Input (+5V) - Ground - Output (+3.3V). I would clean the affected area with a toothbrush and isopropyl alcohol.

Datasheets:

OTi-2168, Ours Technology Inc., USB 2.0 FLASH DISK CONTROLLER, 3.3V:
http://www.datasheetarchive.com/pdf/get ... pdf&scan=n

K9W8G08U1M, Samsung, 3.3V, 512M x 8 Bit / 256M x 16 Bit NAND Flash Memory:
http://www.datasheetcatalog.org/datashe ... 215_DS.pdf

Re: 2 diode burnt?

June 6th, 2011, 0:50

i can handle this case. do you need any help?
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