PA suffers from moving

[mispeltyoof]

We have a Carlsbro 150 PA. It hasnt been used for a while. When we arrive at a gig it crackles and bangs for the first hour then its fine until moved again. In the rehersal room its fine but is stationary. What could be the problem?. If we could set up two hours before going on stage there would be no problem. Any ideas guys? Help please!Drivng us mad.

[Enzo]

Ball up your fist and whack the top of it. Does that start it crackling again? Or make it stop? Some loose connection would be my first guess. COuld be a cracked solder connection that clungs tighter after it warms up. Then the next move shakes it loose again.


Inside I would be listening to the noise while I poke each part on the board with a wooden stick.

And isolate the problem. Does turning the master volume down to zero stop the noise, or does it continue?

[mispeltyoof]

Master volume doesn't affect the crackling( very loud destroys the act totally .)Thanks for reply will get my singer to poke with a stick . He's expendable

[Enzo]

If the master has no effect on the noise, then it is coming from the power amp.

I am serious about the stick. A wooden chopstick is fine - with or without the fried rice. The wood is an insulator, so electricity won't conduct through the stick. Unless the stick is wet, so forget the rice. We could call it an insulated probe if you prefer.

By gently pushing on each component - yes, while it is running - we hope to discover if any part has a loose solder connection.

We also have something in electronics called freeze spray - a spray can that instantly chills parts down to 40 below zero. If there is something that warms up and then behaves, chilling it might make it go back to misbehaving - and thus identify itself.

Loose connections or cracked solder are different problems from thermal sensitivity, though the two can happen together.