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Waldo

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Everything posted by Waldo

  1. audioguru, Thanks for the quick response. I was able to navigate to one of your previous posts (page 55) and download your parts list (rev3) and schematic (rev2 11/09). I assume these are the most current based upon previous posts? thanks for your help, I'll post a picture when my rebuild is complete.
  2. I have a little predicament that I could use a second opinion on. Problem Yesterday I was charging a 12v battery (13.4v @ 1amp) and everything was great until I turned off the power supply and switched it back on without disconnecting the load. I ended up burning out my 2n2219. In hind sight, I've burned out 2 previous 2n2219 transistors under similar circumstances. Proposed Causality I speculate that this occurs because... while under load with the power supply off, the load is leaking back through my circuit. I have verified the function of D10 and R16 and they are in good working order. Is it possible that the current from the load is leaking back into my circuit through the power transistors (2n3055) and causing U2 to overdrive the base of my 2n2219? If so would a protection diode (like D10) placed between the emitter and collector of my power transistors solve the problem? I may be very much mistaken, I could use a second opinion. I've got one 2n2219 left (more are on the way) and I would love to find a fix before I burn out anymore :) Thanks
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