Power Amp immediately blows fuse at power on, any idea's?

[StratBastard]

Hi, I just picked up a really clean Audio Centron RMA-1600 power amp. It immediately blows the fuse as soon as the switch is flipped on. I opened it up and looked around inside and I don't see anything visibly burnt.

I got the amp at a garage sale. The guy said it was used in his church for several years and then during a performace it just blew a fuse. He said he went to radio shack and got some fuses and it did the same thing. So now here it is.

Where should I start at?

I'm kind of a newbie but not an idiot. I have repaired a few things before and know how to solder anyway,lol!

Any help would greatly appreciated.

[andyjazz]

In a tube amp with this symptom, the general rule of thumb is to remove the rectifier tube, turn the amp on, if the fuse doesn't blow, it's the rectifier. I've had this happen a couple of times. The same principal applies to SS amps. Check to see of the diodes in the SS rectifier are good. fairly easy thing to check.

[defaced]

Other relevant thread from this issue: http://music-electronics-forum.com/t20700/

[Enzo]

ANy amp that blows fuses, the output devices are always the first suspects. Sure, check the rectifiers, but really, shorted output transistors are the most likely failure.

[52 Bill]

In a tube amp with this symptom, the general rule of thumb is to remove the rectifier tube, turn the amp on, if the fuse doesn't blow, it's the rectifier.

It may be the rectifier. When you remove the rectifier tube you also remove all of the high voltage from the rest of the amp, thereby removing any possible signs of problems with the other parts of the amp like shorted filter caps, bad tubes, etc.

[J M Fahey]

Quite possible in a Tube amp, yes, but even without asking, the very label "Audio Centron 1600 power amp" strongly (that's an understatement) suggests an SS Power Amp.
Most certainly aluminum and steel clad rather than dressed in Tweed.
StratBastard: start by saying something else about your amp.
I think these guys can help you.
http://www.google.com/url?sa=t&sourc...Zg8beskWAQKQVw
You can get that schematic and post it here; otherwise suggestions can't be very specific but only general purpose.
Good luck.

[Zipslack]

Another thing to check...

Enzo might remember helping me with a similar problem on a Peavey keyboard amp...after checking the outputs, check the filter caps. Shorted filter caps = large inrush/short across secondary = blown fuse. Also, check and possibly replace the rectifier diodes (if it is SS..and make sure to put them in the RIGHT DIRECTION).