[sdiy] How to find a short-circuit? (Vox organ problem)

Antti Pitkämäki anpitkam at hotmail.com
Thu May 17 19:59:55 CEST 2007

Hi again,

Thanks Jean-Pierre for the tip. Update: My friend removed most of the 
boards, including all the oscillator cards, but the power supply output 
voltage still drops. There are still some cards where the problem might be, 
and trying the removal of these will be done tomorrow. My friend already 
replaced the power supply caps. He will also try to disconnect the power 
supply and load it "artificially", to really see if the power supply is 
working - who knows, maybe there's something else wrong than the caps. I 
hope the problem will be found soon!

BTW, in the power supply, there's a big transistor, which is most likely 
OC35, or possibly OC36 (messy schemas). My friend wondered what is its 
purpose. He suggested, that it it has something to do with the fact that 
when the supply is turned on, the positive voltage rises slowly to the 
correct voltage (when disconnected from organ, I assume), it takes like 15 
seconds. He suggested that this removes any possible "pops"-sounds to be 
heard from an external amp when the organ is turned on or off or something 
like that. What do you gurus think? Here's a link to Connie 2 schemas if 
anybody wants to check it out:



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