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I hope to repair a PCB for a hard disk drive which has a burnt out SMD component. It has a connection at each end, with a polarity(?) line at one end. It has "ON" in a circle, and "QA" and "RA 14." written on it.

I have searched on line with no success. Can anyone identify this component?

  • 4
    \$\begingroup\$ Please add a good photograph of the part on the PCB - we need to see it and have some contact for what you are trying to repair. But it does sound like a Diode by "ON semiconductor". \$\endgroup\$ Jul 28, 2021 at 10:22
  • \$\begingroup\$ 4donline.ihs.com/images/VipMasterIC/IC/ONSM/ONSMS15066/… is my best guess based on the information provided \$\endgroup\$ Jul 28, 2021 at 10:31
  • 2
    \$\begingroup\$ That component did not burn without a reason. Most likely the reason is that there is a problem elsewhere in the circuit and replacing the diode will make it burn again and thus replacing it will not make it work. \$\endgroup\$
    – Justme
    Jul 28, 2021 at 10:51
  • \$\begingroup\$ This is a duplicate of the question here. However since I got the accepted answer on that one, I (as a mod) should not close this one as a duplicate of that one, as that could be perceived as a "conflict of interest". However, if others agree, I recommend closing this one as a duplicate. \$\endgroup\$
    – SamGibson
    Jul 28, 2021 at 13:46
  • \$\begingroup\$ @SamGibson Recommend putting more information, such as the "QA" code, into the title of that previous question then, so people searching might actually find it. \$\endgroup\$ Jul 28, 2021 at 14:19

1 Answer 1


Looks to be a ON-semiconductor NSA5.0AT3G. Device specific code "QA".


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