Carvin BelAir Accutronics reverb tank code...?

[Diablo]

Have you looked at the output transducer? It may be repairable. Tedious, but repairable.. Many times it's just the lead wire has broken.

Yes, I tried to repair the output transducer, but failed miserably. I disassembled it by drilling out the brass rivets. Started to unwind the bobbin to look for the break, but couldn't figure out how to remove the varnish/enamel(?) on the wire to make continuity measurements. At this point, I have a couple of choices. Order a new tank from Korea, by way of Germany ($$$$) to ship to Indiana. Or order a tank from Amplified Parts, with the right output transducer, and swap in my good old input transducer.

[g1]

If the input side is still good, your last idea should work fine, or buy a cheap tank with the right output transducer and put it in your tank.
But it will need to be the same manufacturer, for example, Mod transducer blocks will not swap in to accutronics, and vice versa.
At least not easily, the footprints of the blocks are not the same.

[nickb]

Not sure where you are but Tube Amp Doctor have them. You can use a 9FB or 4FB at a pinch - they will work but will be a bit weak.

EDIT: Uh, I see you already had spotted the German source. Sorry I couldn't help more.

[olddawg]

Yes, I tried to repair the output transducer, but failed miserably. I disassembled it by drilling out the brass rivets. Started to unwind the bobbin to look for the break, but couldn't figure out how to remove the varnish/enamel(?) on the wire to make continuity measurements. At this point, I have a couple of choices. Order a new tank from Korea, by way of Germany ($$$$) to ship to Indiana. Or order a tank from Amplified Parts, with the right output transducer, and swap in my good old input transducer.

Usually lacquer thinner or acetone on a Qtip works fine or simply heating it with your iron. It's to thin to scrape. Have you totally trashed it? Can you do a resistance check?

[Diablo]

Usually lacquer thinner or acetone on a Qtip works fine or simply heating it with your iron. It's to thin to scrape. Have you totally trashed it? Can you do a resistance check?

I tried to check resistance, and couldn't make a solid connection to the wire. I tried heating with my iron, and an open flame from a lighter (that just burned up the wire). I tried sandpaper too. I didn't try acetone, and thanks for the tip. I lost count of the number of windings I unwound. I guess I just lost patience with that teensy little wire. I also had to bend the laminations to get the bobbin removed. They just didn't design it for easy repair....

[Diablo]

Took another crack at it this morning, and had continuity after I stripped the bobbin of wire and soldered a short piece of copper wire to each end to test. Measured 195 ohms, so I started to rewind the bobbin, and broke the wire in the middle of the wind when I got too aggressive with my drill/winder. Aaack. Time to order a new Accutronics to get a good output transducer to swap in.

[Tom Phillips]

...Time to order a new Accutronics to get a good output transducer to swap in.

Or maybe find a pickup winder to re-wind you existing coil.

[J M Fahey]

That wire enamel is designed to evaporate at soldering iron temperatures and leave behind shiny bright copper.

A gas lighter flame or even a wooden match will melt such thin copper.

[Diablo]

That wire enamel is designed to evaporate at soldering iron temperatures and leave behind shiny bright copper.

A gas lighter flame or even a wooden match will melt such thin copper.

Yes, you are correct. I verified that the wire goes poof with a lighter flame.
I finally fixed the reverb tank by swapping in a new output transducer assembly, and that was a royal pain in the ass. Drilled out the rivet and used a brass screw and nut to put the new one in place. The difficult/tedious part was I desoldered the wire that attaches to the magnet attached to the spring. Inside each of the three copper tubes is a piece of rubber(?) membrane, and you have to poke the wire through the membrane to solder it to the far end of the tube. I had to cut the wire to get a good stiff and straight piece that would poke through. That didn't leave any extra wire to make a loop for soldering, like Accutronics makes at the factory. I hope the solder joint holds solid. The reverb works...for now.

I thought of a better way to perform this surgery. I should have just clipped the springs in the middle, and figured out a way to patch together two halves of the spring. That way I wouldn't have to touch the solder joints and stiff wire for the other end near the little magnets. Next time.