Need help with Session 500 problem

[Jim Bates]

Last weekend I played in a old dance hall that probably had low voltage. After about 3 hours, my Session 500 started losing all of the full sound and got very weak and tinny sounding. The amp was very hot to the touch, which is what I have experienced before with low voltage. ALSO, I had the amp repaired recently and had not noticed that the speaker was plugged into the "External" jack instead of the "Internal" jack. Would that have caused my problem?

Thanx,
Jim

[John Daugherty]

Have you tried the amp in a different location to see if it is OK now?

[Ernie Renn]

I'd guess that the brown power caused the amp to overheat and it, in turn, caused a portion of it to shut down, at least partially. Check it again to see if it does it, as John said, in a different location. Peavey amps are pretty resilient. Good luck!

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My best,
Ernie

www.buddyemmons.com

[jim milewski]

and if it isn't blowing fuses no output transistors are shorted which is good, is it working at 117 vac and speaker plugged to INT, those massive heatsinks may have saved your amp

[Jim Bates]

Thanks for the help. Ijust checked out the amp. It seems to be working fine with the speaker plugged into the "External" jack. The "Internal: jack is dead???? I guess that is why the repairman had plugged it into the external. Looks like I need to check the schematic and see if something else is wrong.

Thanx,
Jim

[jim milewski]

ya, better check it out, I think it changes the impedance using external, I would wire direct right off the output of the power amp, I don't think a Session 500 needs an external speaker

[Jim Bates]

Update! After checking the schematic and pulling out the power amp, I found that the 3-pin plug, powering the auto transformer, had been left disconnected by the last repairman. Plugged it back in, and both internal and external speaker jacks now working as they should.

Thanks for all your help.

Jim