Gibson Falcon Amp GA 19RVT

[angelodp]

Hi Guys, working on an old Gibson Falcon amp, sounds wonderful. Only issue is the centralab 2Meg Reverb pot which is completely jammed. I mean I have the sucker out and taken apart and it still does not turn? I pulled the small wire clip, nothing. Its just locked. Even tried that stinky lock release stuff.

So I will get the new 2 Meg pot but for now will a 1Meg pot work in that spot?

best Ange

[Reeltarded]

Yeah, just not the same.

[angelodp]

Ok, just put a 60 watt iron ( 700 degreeeees ) on the shaft and managed to get it unstuck. Cleaned her up and will pop back in, good as new.

Cheers and thanks

A

[Firestorm]

Ok, just put a 60 watt iron ( 700 degreeeees ) on the shaft and managed to get it unstuck. Cleaned her up and will pop back in, good as new.

Cheers and thanks

A

REALLY!!! Can't believe that worked! Got to make a note.

[LeftyStrat]

REALLY!!! Can't believe that worked! Got to make a note.

Same here, thanks for sharing. One more in the bag of tricks.

[angelodp]

Although the pot is up and running the reverb is not. I do get that reverb crashy sound when you shake the amp but no reverb to speak of. Checked the pan, it seems fine, checked the rca connectors. When I do engage the reverb foot-switch I get an increase in hum but no reverb. Tubes are fine, caps are old but still working, the map sounds pretty good otherwise.

Any tips on trouble shooting this baby.

BTW on the centralab pot, it was so jammed.... seems like it was a very hard crud that had gotten in there somehow and frozen the thing. Heat really did the trick.

[Firestorm]

If the reverb "crashes," the recovery side works. Must be the send side. Don't have the circuit in front of me; how is it coupled?

[Cliff Schecht]

What Firestorm said. If it crashes the recovery side is working. To start tracing the problem, start at the point where the preamp feeds into the reverb circuit and poke it with an oscope or audio probe. Keep moving forward in the signal chain until the signal dies. It could be a bad (leaky) cap, a bad socket connection or a bad reverb transformer (these amps are infamous for this btw so look here!).

[rp]

REALLY!!! Can't believe that worked! Got to make a note.

Same here, thanks for sharing. One more in the bag of tricks.

+1. As heat did it I think the gunk was the original grease that turned to stone. Seen it in other things. Brilliant tip.

For my 5C8 I got a NOS 2MA off ebay - only took a year too!

[Phil_S]

Call Steve at Apex Jr. He might have a NOS or used Centralab pot of the correct value. I can't believe (no disrespect intended) you can stick a 60W iron in a pot and it will still work properly even though it's unstuck.

[rp]

I can't believe (no disrespect intended) you can stick a 60W iron in a pot and it will still work properly even though it's unstuck.

I think he heated the shaft/bushing part. I bet you can get away with that.

[angelodp]

Yes it was the shaft.... machinists trick to get parts unhung, with heat. These centralab parts were made really well and the heat did not deform or smoke any parts.

[Cliff Schecht]

Angelo do you still need 2MA CentraLab pot or did it actually work (i.e. not scratchy or intermittent) after you heated it? I have some good quality 2MA and 3MA pots that are either Centralab, CTS, Allen Bradley or similar quality units..

[angelodp]

Hi Cliff, thanks for the offer. I had to button up the amp before getting it going on reverb. The owner has it and I might get back inside shortly. I'll let ya know.

Thanks