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I've got a SWR 350 red face amp here. About 6 weeks ago it came in with a fairly common problem which was the power supply capacitors were loose and it was making a lot of hum. I installed new capacitors, looked around, and blessed it. I also installed a new fan and let the amp heat soak for about six hours and it was fine-even though I was using a guitar to test it.
Three weeks later I get a call, it's acting badly and getting hysterical, so I go and pick it up, take it back to the house, hook it up to the speaker and it starts doing this rapid fire sound like a 20 mm cannon. So I shut it off, figure that my cap job's to blame, and order up another set.
Actually it sounded more like a .50 cal Browning M1919A2 machine gun.
I installed them, cleaned up everything and put 'er back together and although it does not go into auto 20 mm rapid fire by itself, it will if you play notes on the bass strings up around the 12th fret. Sometimes you'll get a single pop, or other times it'll go into rapid fire mode and you have to shut it down.
I did install a new fan of a similar rating. The original was rated at 43 cfm and I installed a 39 cfm fan, and it works well. The fan comes on when the surface temperature of the heat sink reaches 143 degrees and it shuts off when the surface temperature declines to 139 degrees. The exhaust duct air temperature is about 104 degrees when the fan is running.
I have limited knowledge when it comes to solid state amps. I'm trying to learn but this is a hard way to do it.
Does anyone have any idea what the heck is going on with this amp? What to try next? I do have a scope and signal generator but I am not yet capable of using them.
Thanks all.
Three weeks later I get a call, it's acting badly and getting hysterical, so I go and pick it up, take it back to the house, hook it up to the speaker and it starts doing this rapid fire sound like a 20 mm cannon. So I shut it off, figure that my cap job's to blame, and order up another set.
Actually it sounded more like a .50 cal Browning M1919A2 machine gun.
I installed them, cleaned up everything and put 'er back together and although it does not go into auto 20 mm rapid fire by itself, it will if you play notes on the bass strings up around the 12th fret. Sometimes you'll get a single pop, or other times it'll go into rapid fire mode and you have to shut it down.
I did install a new fan of a similar rating. The original was rated at 43 cfm and I installed a 39 cfm fan, and it works well. The fan comes on when the surface temperature of the heat sink reaches 143 degrees and it shuts off when the surface temperature declines to 139 degrees. The exhaust duct air temperature is about 104 degrees when the fan is running.
I have limited knowledge when it comes to solid state amps. I'm trying to learn but this is a hard way to do it.
Does anyone have any idea what the heck is going on with this amp? What to try next? I do have a scope and signal generator but I am not yet capable of using them.
Thanks all.
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