Peavey Basic 112 50W bass amp

[Tbass]

Though Ive got some experience with music electronics, tube amps primarly, I have a vast ignorance of solid state/transistor amps. Ive got the schematic for this, my little apartment amp, and I can take measurements with my vom.
amp history: 1. distorted sound/ speaker swap didnt fix 2. bad connection sound when input jack wiggled/ resoldered jack didnt fix These past problems may be related to present problem, or not.
amp now: with no input, makes loud squealing sound and 1 transistor (there are 2 on the heatsink with a smaller one in the middle) gets verrry hot.
With the clues Ive got so far can anyone tell what this problem is or tell me what to check next?

[Enzo]

What is the exact name on the schematic?

Is your loud squeal high pitched, like an infant screaming?  Or is it a loud BRAAAZZZZZ like you were touching the tip of a guitar cord with a finger?  Look at the speaker cone, does it move one direction and stay there?  That would mean DC on the speaker, check with a meter.  Not good for the speaker by the way.

Disconnect the speaker, does that part still get hot?

I am looking at drawing 99010700 from 27 feb 2001.  See the headphones jack?  Right next to it on the schematic is 22 ohm R149.  Is it open?  On the board it is right near the phones jack also.  That resistor is part of the stability network.

[Tbass]

Well thanks Enzo. Heres what  I found: no speaker - no symptoms, so I checked the polarity of the speaker output wires and found I had them reversed.  When I powered up after correcting this screw up, no symptoms! LOL. However, the previous possible input jack problem persisted.  

amp history: 1. distorted sound/ speaker swap didnt fix 2. bad connection sound when input jack wiggled/ resoldered jack didnt fix These past problems may be related to present problem, or not.

I replaced the small resistor  next to the input jack and the bad connection sound went away but input sounds a bit overdriven now.  Next step is confirm I used the correct resistor. Also, Im wondering if I damaged anything with my screwup. Thanks again!