LSC- sparking problems?

[alistair]

Hi guys,

Before I go any further, I want to say that the amp is going in to the tech tomorrow- I'm just looking for a possible explanation first.

I've got a early 2000's LSC that I'm trying to sell- It's a great amp, I just have managed to get my hands on a IIC+ and a 63' Fender Bassman in the last couple of months that suit me a little better.

Last night, somebody interested in the amp came over to try it out- and it was buzzing like crazy. Changed leads, guitars, etc, it was still buzzing at a high level.

After he left I changed some of the tubes around and managed to greatly diminish the buzz- so I will get the tech to retube and hopefully that will fix the buzz but...

I unplugged the amp and moved it to a different power point just to see if that was the cause of the amp. When i plugged it back in and turned it on, a bright blue spark a couple of inches long came out of the back of the amp. It was visible from the front of the amp. Any idea what this is? I've never seen anything like it. It doesn't seem to have done any damage, but it was pretty strange.

 

[boogiemon]

dunno what the root cause might be, but i wouldn't plug it in again until it comes back from the shop.

good luck

 

[BobL]

The only thing in a power supply that would be able to produce a spark as long as you describe would have to be a component with a high charge. That pretty much narrows it down to a high voltage capacitor, probably a filter cap that let go.

 

[pjlcc14]

I've heard tale of such thing........St Elmo's Fire ........alas, none other than St Elmo's Fire........beware for the devil may abide in that amp me fine friend. :wink:

 

[songrider]

I had something similar happen to me in a Lee Jackson amp... it wasnt a spark though, it was a blue flash in my case. turned out to be a bad power tube.

Popped in a new quad and biased it up and it was good to go.

 

[alistair]

maybe a bright blue flash is a better description? I'm not sure, it was over in a split second. It came from the area above the rectifier tube so I'm not sure what is near that on the circuit board.
Thanks for the help guys.... im hoping it was just a tube!