FBT PA is distorting when warm

[Bluefinger]

Hi,

My old FPT PA is acting up lately. It's one of those PAs with two bass speakers on the floor and another speaker cab on top of each one. When you turn it up it sounds really great but after a while the upper speakers start to distort - not necessarely both at the same time. I guess it's a heat related problem. The mixer and cables have been ruled out. It must be somewhere in the PA. Are there any obvious reasons for this? Any ides?

thanks!!!

[Jazz P Bass]

Have you attempted to contact the manufacturer?
Email: mailto:info@fbt.it

Web site: FBT Elettronica S.p.a - Professional Audio Equipment

[J M Fahey]

We need more data.
What model is your "old FBT PA"?
Are the speakers passive or active?
A couple pictures, showing the cabinets, the connection panels, the mixer or power amp would help.
Write FBT stating model and serial number and ask for a schematic, tell them the Service Tech asked for it.
Do you have any user manual for it?