<html><head></head><body><div>As long as the voltage and current ratings are covered almost any transistor will do electrically.</div><div>Note that the 2SD1762 has an insulated tab so find one with the same if possible, or you'll need an insulating kit.</div><div><br></div><div>Martin</div><div><br></div><div><br></div><div>On Sun, 2023-02-19 at 15:02 +1300, Spencer Travers wrote:</div><blockquote type="cite" style="margin:0 0 0 .8ex; border-left:2px #729fcf solid;padding-left:1ex"><div dir="ltr"><div>I am repairing someone's much loved audio amp/receiver from the 1990s and need to find a replacement transistor. It is a 2SD1762DEF TO-220 NPN bipolar power transistor. Some datasheets say it's 50V, 3A rated. There are some ebay listings for this part.</div><div><br></div><div>Does anyone have something local and suitable or some pointers? I do have a service manual with schematics. If anyone's interested, here is a link: <a href="https://drive.google.com/file/d/1DhsyuLpafuNbXBOhnIgTRilbyw64tCRr">https://drive.google.com/file/d/1DhsyuLpafuNbXBOhnIgTRilbyw64tCRr</a></div><div><br></div><div>Q701 is the dead transistor, located at grid 32B in the schematics.</div><div><br></div><div>This transistor is used to create +15 V from the +40 V rail. It looks like the audio input selector IC401 shorted +15 V to -15 V and took out the transistor along with a couple of traces on the PCB. R405 & R406 and surrounding traces were destroyed. The good news is that injecting +15 volts from a lab PSU to where Q701's emitter was connected seems to make the amp work OK.</div><div><br></div><div>I had thought of using a 7815 voltage regulator but I think the input voltage would be too high. I do see some devices on ebay and may have to resort to that.</div><div><br></div><div>I guess another option would be to add a separate transformer, rectifier, and voltage regulator to get 15 V, but I would rather avoid that. Unfortunately there are no suitable lower voltage taps on the transformer.</div><div><br></div><div>Spencer</div></div><div>_______________________________________________<br></div><div>Chchrobotics mailing list <a href="mailto:Chchrobotics@lists.ourshack.com">Chchrobotics@lists.ourshack.com</a><br></div><div><a href="https://lists.ourshack.com/mailman/listinfo/chchrobotics">https://lists.ourshack.com/mailman/listinfo/chchrobotics</a><br></div><div>Mail Archives: <a href="http://lists.ourshack.com/pipermail/chchrobotics/">http://lists.ourshack.com/pipermail/chchrobotics/</a><br></div><div>Meetings usually 3rd Monday each month. See <a href="http://kiwibots.org">http://kiwibots.org</a> for venue, directions and dates.<br></div><div>When replying, please edit your Subject line to reflect new subjects.</div></blockquote><div><br></div><div><span></span></div></body></html>