ok, then I'm not crazy! So back to the shorted cap, wouldn't some current still make it into the cap and charge it slowly over time?

 

Only a tiny charge separation could be held in the capacitor, in response to a tiny voltage developing across the shorted leads as a high current passes through. As soon as that current stops, the tiny voltage disappears and the charge would rapidly equilibrate through the shorted leads.

We're still reserving judgement about the crazy bit.

 

Hi all, I have a home audio amplifier that I am trying to fix and I was wondering what category I should post my thread. There is a bridge rectifier on the power supply board that has quite a large spark when I first power it on. The spark appears to jump from the positive lead to the negative lead. I've replaced the bridge rectifier and the 2 small caps next to it, but it still sparks. The amp still seems to work but I do want to fix the large spark.

Hi MilkyTech, I realize this thread is 4 years old, but coincidentally I just googled “my AudioSource Amp300 sparks when I turn it on” and this popped up. I haven’t video’ed it like you did. But it for sure is coming from the same area as yours. I read through all the posts and it seems that your just taking it out, straightening some posts, and messing around with it, fixed the problem. I’ll attempt that myself tomorrow. I’m wondering, am I the only one that has reached out to you with the same problem on this amp? Also wondering if our serial numbers are close (or in series). I was nervous because I just last week blew out/dusted and applied deox to the entire unit, as a general maintenance. I was noticing some right channel problems and thought it might be my aging amp. Looked for capacitor issues, found none. So I gave it a good cleaning. Now it sparks on the power-up. By the way, my right side issue was an RCA cable problem. Seems the copper shielding that had been trimmed and covered with shrink wrap wasn’t trimmed enough and some copper was making contact with the plug (on both ends). I ended up clipping off both plugs and re-soldering the negative ends, one with the shielding and one without. Now that problem is gone, but I’m suddenly afraid of fire when I turn on my stereo.