Vintage SG 812 PM repair

[M3D!C]

hey guys new to the forum here.

so for my birthday not too long ago my band mate gave me a CMI Amp model SG 812 pm.
he said that he's played, but only when its upright. when its on its side, no signal will come out.
after i had played it i turned the knob all the way and the signal is weak .
upon further examination i found that one the speakers had been ripped and had been repaired with ductape.

although i still consider myself a novice in audio electronics. i just dont know how to diagnostic this problem

what do you guys think?

i will also post pictures down below

 

[PRR]

> ripped and had been repaired with ductape.
> i just dont know how to diagnostic this problem

I just got an old tractor. It has oil-stains. I just took the grille off and found duct-tape on some oil hoses.

While I am a novice in tractor repair, I'm thinking I need to find out what is under the duct-tape. Is it only decorative? Or is there a leak which needs fresher duct tape? Or maybe even a new hose?

Speaker coils can rub in the magnet, especially when the paper has been torn.

They can even get "stuck".

And sometimes depending which way gravity is sucking it.

An odd thing is: a "stuck" coil usually is not "dead". There's no bass, but treble shakes its way out.

Why do you want to play it on its side??

You could, perhaps, unscrew the speaker, turn it 90 degrees, and remount it so it is happy on its side.

However duct tape is short-term at best.

A skilled technician can repair accidental rips with rubber cement and tissue or cheese cloth. However an over-abused guitar speaker may be cooked and torn so far out of shape that it can't be patched.

As a quick-test, to be *sure* it is the speaker and it isn't a loose electronic part, patch any known-good speaker in place of the dubious speaker. Don't play loud/long, just enough to verify/deny the speaker is the problem.

For a real fix, you need a speaker of the *same* impedance range, similar flavor (not a subwoofer etc), compatible physical size, and same (or a bit more) power rating.