Peavey Combo 300 no output

[jamble]

I have a problem with a Peavey Combo 300, where when the amp is turned on there is a massive noise that increases in pitch and amplitude(gets really loud and then stops and then none of the amps functions work and there is no output from the speaker. Any ideas? And does anyone know the name of the conection to the speaker as well incase I need another amp.
Many Thanks.

[Jazz P Bass]

Peavey 300

I do not quite understand that last part about the speaker.
The noise could be the power supply failing.
Then again it could be anything else. Preamp, output section.
If you are trying to repair this piece of equipment, you must work the problem.