Gibson Falcon GA-19RVT

[bal704]

A friend recently bought a Gibson Falcon at an estate sale. It was supposedly bought new in the early 1960's, and hasn't been played since the 1980's.



There are 2 cap cans, that are the paper Astron type. I've never seen one of these in person, but the ends appear to be bulging out. There was apparently some repair work done in the past, where 2 radial caps were jumpered across the bottom cap can. There wasn't any such work done on the top cap can.



I've circled where the ends are bulging out. Are these defective at this point? The 2 radial caps should take care of the filtering, but will the cap can still being in the circuit cause a safety issue?

Also, there is a cap from the power switch to ground. This has the 2 prong electrical connector. What does the cap do?





Lastly, my friend wants the 2 prong connector replaced with the modern 3 prong variety. The current cord is pretty skinny, and the chassis hole for it is fairly small. Where can I find a suitable replacement that will fit without drilling?

[tubeswell]

Wow - that's a tidy/stunning looking example of a Gibson! Inside and out!

Yes you should definitely recap those old e-caps in that amp. Them ole caps are no good. Use 'equivalentish-capacitance value'* caps, with the same or higher voltage ratings as the originals

* this is a 'loosely equivalent' concept where, for instance, 16uF=20uF=22uF, 40uF=47uF=50uF, etc (incidentally 10MF = 10uF, and where you have 10MF+10MF, you need to check whether both 'sides' of that 'cap-can' are in parallel on the same power supply node, or decoupling different power supply nodes. If they are in parallel, you can use 1 x 20uF cap to replace it etc, or if they are holding up different nodes, you could equally use 2 x separate 8uF=10uF=16uF caps as replacements, and so on)

[bal704]

One side of the 10+10 is feeding the PI, the other side is feeding the preamp.

Is it safe to leave the old cap can connected if I add a pair of 10uf caps? Th 20+10 cap can that feeds the B+ and B+1 is still connected even though the radial caps have been added. The leads on the 10+10 cap can are pretty long. I was thinking I could snip then near the cap can, and run them to the pair of 10uf caps I will add. That will leave the original solder joints in the PI and pre intact.

[pompeiisneaks]

As for the second cap, that's what's called the 'death cap' and it should be removed when you put in a new power cable. I've heard differing fixes for the narrow cable hole, some people just use a typical chassis bushing and put a zip tie on the inside to stop slippage, but others either drill out a slightly larger hole, or some I've heard mention found a smaller sized 3 prong cord, but I can't recall where that comes from off the top of my head.

There's possibly a 'ground' switch which is useless, if not dangerous with a 3 pronged cable, so remove that from the path of power too.

~Phil

[Phil_S]

The death cap is probably .02uF and is a desired item you can sell on eBait for maybe $5-$10. If you can test for leakage and it's not leaky, it will fetch the higher price. Or you can save it for personal use. In any case, remove it. My caution is about preserving lead length rather than simply clipping it. Others' comments about the 3-prong problem -- nothing to add, but please do something.

I am not such a purist on the orange cardboard Astrons. If it was mine (and I did this on my GA20-RVT), I'd drill the rivet and remove them. The hole in the chassis will allow you the opportunity (if you just think out of the box a little) to place a clamp for a new short format multi cap, or to simply bolt on some kind of strapping for new caps or insert a terminal strip. If you go with a terminal strip, cut the old wires close to the cap and you can probably reuse them without disturbing the component end. If you feel that you want to preserve the look, hollow them out and fit new caps inside the old cardboard.

Given the age (c. 1962-64), all e-caps should be replaced.

Nice amp. Enjoy working on it.

[bal704]

Regarding the bigger cap, with the radial resistors already jumpered across it...

Is is safe to leave the leads soldered in place, or will I need to snip/unsolder those?

[Phil_S]

Those 47uF caps are well above the schematic values. I think I'd remove them along with the Astron cardboard ones. The schematic says 20uF-10uF-10uF. If a little more filtering is desired, I might use three 20uF or maybe one 20uF and two 16uF.

Is it safe? It is really hard to see what was done, so I can't say. The rectifier is 5Y3 -- the tube spec sheet says not to exceed 32uF. On that basis alone, I'd remove the 47uF caps. One thing that's obvious is that the Astrons need to be removed before they blow their guts and make a terrible mess.

[pompeiisneaks]

Can't agree with Phil more.

The other Phil.

~Phil

[andresound]

These are great sounding amps. I recapped my 1961 EPIPHONE EA-10RV. This one has a 15 Jensen (P15N). Enjoy!!

[rp]

Maybe an opportunity to use these? If you can get the old ones out of the rings, not easy, and the new ones in w/o ugliness or find similar fitting rings. Anyways would be a cute repair.

https://www.tubesandmore.com/products/c ... 50v-1010-f

I still think these mint stock untouched amps will have more value one day, even not working, than something restored, that's what's happened to cars. Take out the old parts cleanly, power cord too, and keep then with the amp. One day you can double your fun as an art forger, put it all back, patina the solder joints, throw some dried moth wings and just a few mouse turds inside, add some eau de' vieil étui à guitare and get a premium.