How to service a Carlsbro Scorpion L?

AustrianJohn

I have an old Carlsbro amp that has scratchy pots and an intermittent problem. Plan was to take it apart, tidy up soldering and clean the pots out. So I removed all of the screws that appeared to connect the internals of the amp to the case - but nothing moves.

Is there a magic way of dismantling these amps? (In a way that allows them to be put back together again )

ICBM

I can't remember exactly which version this is - is it the grey one with the controls on the front and chassis securing bolts in the ends - two each side front and back?

If so, either there are some more bolts hidden under some of the plastic trim, or the front and back panels (they're separate) are just stuck to the vinyl, which often happens… I can't remember, it's a long time since I worked on one!

If there's an intermittent cutting-out problem it's likely to be the jack switch contacts in either the FX loop or the headphone socket, this is common on old Carlsbros. Apart from that and scratchy pots, they're actually extremely reliable. 

AustrianJohn

It's this one.



I'll have another go next week and try your suggestions. Thanks @ICBM ;

ICBM

Yes, I thought I remembered right! If you've undone two screws at each end both front and back (eight in total) then there are no more and you don't need to remove the trim. What's then happened is that the metal panels have got stuck to the vinyl - you can sometimes free them by putting a 1/4"-diameter screwdriver into the jacks and wiggling it un and down a bit, but be careful not to damage the jacks. Short of that you'll need to get a flat blade of some sort under the edge and lever it out.

AustrianJohn

@ICBM to the rescue again! The metal tray was stuck to the vinyl, but a gentle thump from behind and it slipped out. Once dismantled, the intermittent problem has gone away (and having put it back together again, problem is still gone). Soldering all looks fine. Gain pot is scratchy, but that will be solved when Mr Ebay delivers some Servisol, which I can't find locally.

ICBM

If dismantling fixed it, it will be either one of the jacks - removing the panels will have flexed it and may have removed a spot of corrosion - or it was the cable connectors between the preamp and power amp, which I'd forgotten to mention. Just clean all those as well as the pots when the Servisol arrives and it should be fine.

These amps really are very solid and reliable otherwise - kind of like a British Peavey. I don't think I've ever seen a dead one, other than for this type of fault. It's a shame most people don't like the sounds these days! Although as they always were, they're still a good pedal platform.

Cabicular

ICBM said:

If dismantling fixed it, it will be either one of the jacks - removing the panels will have flexed it and may have removed a spot of corrosion - or it was the cable connectors between the preamp and power amp, which I'd forgotten to mention. Just clean all those as well as the pots when the Servisol arrives and it should be fine.

These amps really are very solid and reliable otherwise - kind of like a British Peavey. I don't think I've ever seen a dead one, other than for this type of fault. It's a shame most people don't like the sounds these days! Although as they always were, they're still a good pedal platform.

I've tried to kill a few but I can confirm it's almost impossible 
they were a stalwart of rehearsal rooms in the 80s and as such I developed a real hatred for them