Need some advice on a 59 5F11 Vibrolux

[bryanJ]

I was talking with a friend about building amps, so he asked me to look at an old amp that he had about 10 years. He had traded some welding equipment for the amp & a now long gone guitar for his kid to use. He couldn't remember what kind it was, but was sure it was old. His kid stopped using it several years ago because he was getting shocked when he played it. It turned out to be be a 59 5F11 Vibrolux. At first I thought great a tweed amp that looked in pretty good shape I would re-cap & put a grounded cord & life would be great. Then I looked on Ebay and found 3 for sale all over $2000. This one is certainly in as good of condition as at least one of them. Now I want to make sure I don't do anything that might drop the value.
The current condition: The tweed on the cabinet is mostly in good shape, but worn thru in a couple of the corners. It has been worked on previously 1 coupling cap was replaced with a orange drop & both preamp cathode bypass caps were replaced with Sprague Trans-lytic 50uF 25v caps. The output transformer was replaced with a Stancor 18w universal and the Selenium rectifier for the tremolo was replaced with a diode.

Everything else looks original including the Sylvania 6v6 power tubes, GE made in England 12AX7s, Jensen 10 in alnico speaker, Astron caps & power tranformer stamped 66079B.

First observation was pins 3 & 4 going to the plate & screen of the power tube closes to the rectifier (V4) have some kind of green corrosion on them. The filter cap for V1 has a "blow out" on the voltage end. The amp powered up and made sound, but was noisely. I did want to play with it much because of the shocking thing.

I put a guitar cord in the input and measure about 110 mv AC between the tip and ground, 0 volts DC.

Here is where I'm at now. Since the OT was already non-original I ordered a mercury magnetics Tone clone replacement. I am looking for an Astron yellow cap to replace the orange drop that was put in. Seem to be plenty of those on Ebay just need to find the right value.

Here is where I need the advice: One of the Astron minimite 16uf filter caps is obviously bad, should I go with a Sprague Atom? Should I change all 3 & what will that do to the value if I do? I would suspect good modern caps have to be better than bad original. The cathode caps that were already replaced are 50uf, the original Astron Minimites were 25uf 25 volt. Should I replace these going back to 25uf and any recommendations on what I should use. The power tube cathode cap is original minimite, should I change it to be safe? Should I go back to a Selenium rectifier or just leave the diode as is? Should I keep the original power cord or go to a ground cord for safety? I have read before that this particular mod has no effect on the value.

Anyway I have used this board for years, but this is my first post. I know there are many guys on this board t vastly more knowledgeable than myself. I hope some of you guys can help me out on this before I make a mistake.
Thanks,
Bryan

[David Root]

You've already established a shock hazard existing. You have to get to the bottom of that, #1. You have to change all the power supply caps, #2.

Sprague Atoms work, but if you want to maximize value, find some correct uF and voltage electrolytics that fit inside the Astron cases reasonably snugly. Slice the paper cases axially and put the new caps in. Replace the caps so the cut line doesn't show.

Then check the amp out for ground faults again. If OK, it may not be absolutely necessary to put in a modern three pin power cord, but it is certainly advisable. If it's still bad, change out the power cord to a modern 3-pin. If that doesn't fix things look elsewhere. Check out the PT, does it blow fuses?

The power tube cathode cap is suspect. Does it leak DC? If so replace it. The preamp cathode bypass caps are fine at 50V, so long as they are still good.

The OT is a problem. Non-original OT is a big hit to the vintage value. If you can find an original OT well & good--good luck! Otherwise the MM clone will at least sound good.

I could be wrong but I think the germanium diodes can still be had as repros but I don't recall details.

Take out the tubes, clean the sockets, check for any evidence of arcing. Seems unlikely but that shock hazard is coming from somewhere.

Show us some pix, that would help I think. You have a potentially great find but if you sell it and it electrocutes the buyer, you're in deep s**t.

[PaisleyTube]

remove the (maybe leaking) death cap

[bryanJ]

David, the fuse did not blow, but I found a 30 amp fuse where a 1 amp should be. Here are some pics, but my camera is pretty crappy, so the resolution isn't the greatest.

Also I talked to the owners son. He says he only got shocked when he touched the other guitar player while they played through separate amps.

[David Root]

That looks pretty good. I have seen much worse. The yellow non polar Astrons look fine but should still be checked for DC leakage.

30 amp fuse!, might as well have been a finishing nail! Put in the proper 2 amp fuse then try it again.

[Cliff Schecht]

Can I buy your Astrons?

[Gibsonman63]

Definitely ground the chassis. My BF amps used to shock me the same way before I grounded them. The temporary fix is to flip the ground switch or turn the plug over.

It's much much worse when you get shocked on the lips from your microphone while playing through one of these ungrounded amps.