john-seaton 0 Posted October 7, 2014 in Repairing the LEDs PWM My LEDs shorted out and blew the main board's PWM control circuitry. Simon sent me a replacement but I can't help wondering if it is repairable. If I had to guess its going to be a mosfet or transistor that has been blown and this should be fixable. Anyone here attempted this fix before? I have the tools to do SMD work so I'm not too concerned about that and I think I found the schematic on github, I just need to make sure it matches the version of the board I have now. Share this post Link to post Share on other sites
gr5 897 Posted October 7, 2014 in Repairing the LEDs PWM I'm pretty sure there's only one version of the schematic for the UM2 at this point. Any changes to the board have been parts only I suspect - the layout likely hasn't changed. Share this post Link to post Share on other sites
gr5 897 Posted October 7, 2014 in Repairing the LEDs PWM John please specify what country you live in and what machines you own in your profile settings. Share this post Link to post Share on other sites
john-seaton 0 Posted October 7, 2014 in Repairing the LEDs PWM Profile updated Share this post Link to post Share on other sites
john-seaton 0 Posted October 8, 2014 in Repairing the LEDs PWM Yep this should be an easy fix. J15, when shorted sends uninhibited current to ground through the NPN transistor BC817. This transistor has a max collector current of 500ma. Chances are this was exceeded and burnt out the transistor. I believe it is the SOT323 package too. Can anyone confirm? Thanks John Share this post Link to post Share on other sites
