Electronics > Repair
mini-MELF diode ID
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TheMG:
Is there any way to accurately identify mini-MELF diodes?

The ones I'm looking at look basically identical to this picture: https://www.mouser.com/images/marketingid/2021/img/173270389.png?v=070223.1037 (single black band and no other markings).

This is for a Tripp-Lite SU1500RTXL2UA I am trying to repair for someone. Of course, schematics are unobtainium.  The diodes that have gone short form a bridge rectifier rectifying the output of a current sensing transformer. There is another current sensing transformer in the UPS also with a set of 4 identical looking diodes which aren't shorted, these measure around 0.48V forward drop with a multimeter, so I know they are not SCHOTTKY (forward voltage too high) and based on their function in the circuit they would not be zener diodes either, so most likely standard silicon diodes of some kind.

However... no idea about other parameters such as reverse voltage rating or if they are standard or fast recovery time (if that even makes any difference), that type of thing. Based on this current sensing circuit's purpose in providing current feedback to the PFC boost regulator, probably safe to say we're dealing with relatively low currents.

Any ideas on what a suitable replacement might be for these mini-MELF diodes?
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