Help identify this component


Joined Oct 8, 2019
2SB111X series come up as PNP transistors with 1A to 3A rating. If you can confirm it's PNP by using an ohmmeter on a hopefully good junction (EB, BC) I'd go with the highest amp transistor.

panic mode

Joined Oct 10, 2011
i don't think it is a transistor. silkscreen next to it clearly shows IC1 so this is an integrated circuit.
picture of entire board from both sides would be helpful.
if failure was caused by reverse polarity, chances are that this would be a voltage regulator for example.


Joined Sep 17, 2013
A bit of reverse-engineering to trace the nearest half dozen or so components connected to the IC might also help for identification.

Thread Starter


Joined Nov 19, 2019
Thank you for your help everyone. I'll dig further into this.. see if I can figure out if it's one or the other. Your help is appreciated.


Joined Jan 18, 2008
All of those capacitors next to it suggest it may be a voltage regulator (VR). They are usually not very tolerant to reverse voltage. Voltage regulators are often 3-pin devices with one pin connected to ground. The center pin of your device (tab) is connected to copper pours on the top and bottom of the PCB. That is for a heat sink, but could likely also be ground.