SVT 3 Pro Rack Mount not outputting

[jroe]

Hello;
I am having an issue with my SVT 3 Pro rack mount. I believe it is from 1995.

The amp turns on without a problem. If I turn the gain up it will peak but it is not outputting anything. There were two resistors that looked like they were having some issues so I changed them. Everything else seems to be fine.

Any suggestions?

[w0ttm]

Where to start.......
No output can be a ton of things, but most of the time, I find connection issues.
The first thing is the speakers. Check them with an ohm meter.
Check the output with a volt meter without a speaker load connected. If you get well under a volt DC with no input signal, connect a different speaker and see what happens.
Resistors are usually innocent bystanders, so if they were distressed, something else did the distressing.
That being said, amp builders often put marginal parts in to save money. I could tell some stories........
I'm not acquainted with that model. I'm guessing that when you say "it will peak" that an LED indicates some activity.
If this is so, the preamp section is probably working.
Do you have a scope and a signal generator?
If so, send about a tenth of a volt at 500 Hz or so into the input jack and follow the signal path with the scope until it goes away. That will be where the problem is.
Instead of a signal generator, a music source will work, like a computer sound output with the volume set low. A small practice amp can serve in place of the scope, if you are careful not to hook it's input to any substantial voltages, and there are many in a high powered amp.
Good luck........Rob.

[Mars Amp Repair]

for something simple, run a jumper 1/4" cord between the send & return jacks & see if the sound is restored...you can also just send a signal to the 'amp in' jack to circumvent the entire front end of the amp.
if there is no hiss or any indication of sound from the speaker, then all this probably won't help. glen