Peavey Tour 450 Dead?

[Sundogue]

I had my Peavey Tour 450 drop off my cabs a while back. No sound out of it. I finally opened it up today and I can't see anything physically wrong with it...nothing loose, nothing cracked, broken, etc.

It powers up and the power light comes on (along with the fan), but then it appears to shut down (power light goes out, yet the fan still runs).

Anybody have any suggestions as to what to look for? If I could fix it or get it fixed cheap I could always just use it for a spare practice amp.

On a side note, there is no preamp out on this head and I already have a new amphead, but I'm thinking of going the Preamp/Power Amp route sometime. Is there a way to use this head as a preamp only (as in gut everything out of it not needed to power speakers and only leave the components required inside to use as a preamp sans the extra weight)? Not sure what that would entail or if it's even possible. Just a passing thought.

[BbbyBld]

It powers up and the power light comes on (along with the fan), but then it appears to shut down (power light goes out, yet the fan still runs).

It's going into protect mode. Why? I don't know. It could be for a lot of reasons. I wouldn't try to turn it on again. You could make the problem worse.

If I could fix it or get it fixed cheap I could always just use it for a spare practice amp.

You can ship it in to Peavey service and it will be good as new. I'd bet the repair bill would be less than $100 plus shipping.

On a side note, there is no preamp out on this head and I already have a new amphead, but I'm thinking of going the Preamp/Power Amp route sometime. Is there a way to use this head as a preamp only (as in gut everything out of it not needed to power speakers and only leave the components required inside to use as a preamp sans the extra weight)? Not sure what that would entail or if it's even possible. Just a passing thought.

Just come out of the FX send jack on the back. The possible problem you'd face is that the signal out of the send jack is not hot enough to drive a lot of PA power amplifiers. You'd want a power amplifier with less than 1vrms input sensitivity. The input sensitivity of the Tour 450 power amplifier is about 0.6vrms or -2.22dBu.

[Sundogue]

Originally Posted by BbbyBld

It's going into protect mode. Why? I don't know. It could be for a lot of reasons. I wouldn't try to turn it on again. You could make the problem worse.

Hmmm, you know when it fell off the back of the cab, it hit the floor and with the speaker cable not being long enough, it pulled the speakon cord right out of the cab's connector leaving me with two bare wires. The speakon was connected to the back of the amp, but bare wires on the other end. They may have shorted it out.

Is there anything to check for if that's what caused it to go into protect mode? At some point I may have it fixed, but I don't need to at this point.

[BbbyBld]

Is there anything to check for if that's what caused it to go into protect mode? At some point I may have it fixed, but I don't need to at this point.

It may have a shorted power transistor. It doesn't seem too bad off because it's not blowing fuses, so it may be a blown driver transistor only.

There is a slight chance that one of the solder-in low voltage fuses is either blown, or the shock of falling cause it to contact the metal fan box (or the fuses touched each other) that surrounds the main heat sinks. Those fuses are near the fan on the right if you're looking at the front of the amp. If one of those fuses blows, the power amp protection runs off of a backup supply so that the amp won't fail catastrophically, which would be why the amp seems to try starting up.

There is a protection circuit that detects the fan's operation and will shut the amp down if the fan is damaged. You say the fan works, so I doubt that's the problem. You can stop the fan from turning, or unplug the fan, and the amp will go into protect mode, for example.

I don't recommend trying to repair any of this stuff BTW.

[Sundogue]

Originally Posted by BbbyBld

It may have a shorted power transistor. It doesn't seem too bad off because it's not blowing fuses, so it may be a blown driver transistor only.

There is a slight chance that one of the solder-in low voltage fuses is either blown, or the shock of falling cause it to contact the metal fan box (or the fuses touched each other) that surrounds the main heat sinks. Those fuses are near the fan on the right if you're looking at the front of the amp. If one of those fuses blows, the power amp protection runs off of a backup supply so that the amp won't fail catastrophically, which would be why the amp seems to try starting up.

There is a protection circuit that detects the fan's operation and will shut the amp down if the fan is damaged. You say the fan works, so I doubt that's the problem. You can stop the fan from turning, or unplug the fan, and the amp will go into protect mode, for example.

I don't recommend trying to repair any of this stuff BTW.

Thanks for the info. And I agree, I don't know enough to attempt to fix it myself, but the info is helpful whenever I get around to taking it in.