beta bass problems...

[marcm]

hello-
I have bought a beta bass that is working intermittently.  I have it hooked up to a jbl 18 for testing purposes and when I play through it  all it does is push the speaker (i don't know what this is called).  no sound at all.  i am generally fairly good with electronics but am no engineer.  this happens on all inputs.
i have torn the amp apart to check all of the fuses and see if there were any blown bits in there and nothing on the power amp section stood out as looking bad.  I just bought this from someone who advertised on here and figured it would be an interesting project.
any help??
thanks
marc

[Isaac]

What do you mean by "push the speaker?" When you turn it on, does the speaker go in or out as far as it can go and just stay there? If so, that sounds like the amp is putting out a lot of DC voltage.

[marcm]

Exactly!
the speaker pushes and stays there as soon as the amp turns on.
I obviously don't keep it on but for a second after it does this.
I noticed after searching for repair advice on here that Don T. lives in portland.
wonder if I could enlist his help?
any options, things to check voltage on?
I have the schematic by the way.
thanks
marc

[Isaac]

I'll help if I can. Can you email me the schematic?