Ampeg VL502 problem

[michaelolias]

I have a pair of VL502's that have a fade out / break-up problem. Various things seem to fix it for a short time. i.e. pushing the effects loop switch in and out, flipping the stand by on & off or a well placed fist. I've ordered new tubes, pre-amp & EL34's, mine are pretty old. I have also found on another forum that the molex connectors are know to fail due to heat? Im sure that they could use a good cleaning. Any idea's or help would be greatly appreciated.

[Phostenix]

Check out the video series from Lee Jackson on servicing the VL1002:

[ame="http://www.youtube.com/watch?v=Pg2IrwZ6b4U"]YouTube- Ampeg VL-1002 Service and Bias by Lee Jackson Part 1[/ame]

[Enzo]

Squirt some cleaner into the switch and work it a few times.

Power off. Look at all the CLiff style jacks - the ones that lift the crosswise contact when the plug is inserted. MEASURE the resistance betweent he tip contacts and the cutout contacts they rest on. If any measure more than half an ohm, they need cleaning. I use a burnisher myself.

Check the solder under every control and jack for cracks. ALso look at the various largerectangular cement power resistors. Check the solder to them.