SFSR no reverb sound

[Mars-Hall]

Just finished a cap job and converting the bias balance to an adjust.  The amps sounds great, except no reverb.  First off I tried a new tube with no change.  I decided to remove the tank from the bag, knowing those RCA plugs have a tendency to loose ground.  Everything seemed ok there, so I removed the bottom plate to the tank.  I found that the black wire coming from the input jack has broke.  It broke at the spring assembly, at what looks like a clear plastic plug.  Can it be repaired, if so How?

[phsyconoodler]

Without seeing it,your description doesn't mean much.Clear plastic plug?You mean the connector that plugs into the little transducers?

[Mars-Hall]

Without seeing it,your description doesn't mean much.Clear plastic plug?You mean the connector that plugs into the little transducers?

Yes, that is correct.  I didn't realize when I first posted this but it actually is a small plug.  So one of the wires broke away from the plug.  Can it be salvage?

[phsyconoodler]

In most cases yes.If you slide it off the tank transducer carefully and re-attach it to the connector or get another connector.If not you can just solder the wires onto the leads coming off the transducer.But you have to use a heat sink so you won't damage the transducer wiring inside.
  Best to attempt to do the plug.
It sounds like you don't have much experience so maybe get a tech to do it for you.

[Mars-Hall]

In most cases yes.If you slide it off the tank transducer carefully and re-attach it to the connector or get another connector.If not you can just solder the wires onto the leads coming off the transducer.But you have to use a heat sink so you won't damage the transducer wiring inside.
  Best to attempt to do the plug.
It sounds like you don't have much experience so maybe get a tech to do it for you.

I have experience building and repairing amps, but have never encountered any trouble with a reverb tank.  I've managed to get the end of the broken wire out of the plug.  What's the method to re-attach the wire?  Where can a new plug be purchased?  I did not see one in the Hoffman store.

[phsyconoodler]

Solder the wire back on or get a small pick tool and open the little connector in the plug.Use your noggin.

[Mars-Hall]

I would rather use a proven method, than to try and force something unaware, that's why I asked the question.  I did manage to get the wire re-attached, before the benefit of your sarcasm.  The reverb still isn't functioning.  I'll pull the chassis to see what's up inside. 

[phsyconoodler]

Test the reverb tank with a meter first.About 1-4 ohms on one side and approx. 220 ohms on the other side.
  The wiring is a very basic repair but you need to test your work.Don't assume that tank is good because the wires are connected.
 You say you've built and repaired amps,then the basic skills you have but for some reason you are not using them in this case.
 It's not sarcasm,it's reality.
 1) confirm the tank has a reading on both ends,measure across both wires with the cables unplugged.
 2) make sure your repaired wire is making a good connection.
 3) measure each RCA cable for continuity and shorts
 4) replace both reverb driver and recovery tubes with known good ones for testing.
 5) do not be in a rush.re-check all your work
 6) the chassis should be the last thing to come out.

[Mars-Hall]

Ok, you're right, thanks for the reality check.  I figure the tank is bad, this is what I found.

1.  Checked continuity of the wires that go from the tank to the amp chassis.
2.  Checked continuity across input jack and the pins of the transducer = 1.6 ohm.
3.  No reading across jack or the pins, of the transducer, on the output side.

If the output transducer is bad it's time for a new tank, right?

[stingray_65]

If the output transducer is bad it's time for a new tank, right?

Pretty much yes.

The transducers are really pretty fragile and in my limited experience you can patch them up a bit, but nothing that ends up being a permanent repair.

Ray

[Mars-Hall]

The funny thing is, it was the other end of the tank, the input side, that had the broken connector.

[HotBluePlates]

Unless you see something, or get adventurous, you're right about needing a new tank.

But a little encouragement:
If the tank is already shot, there's no harm in attempting to repair the output side. You can't break it any worse than it is now.

You might look to see if you can do any disassembly on the output side, possibly even to the point of unwinding the transducer coil a bit, looking for a break.

It sounds scary, but I did this to repair the B+ winding on a PT inside a old VTVM. Tubes inside lit up, but there was no high voltage to run them. Fortunately, the PT had paper insulation that was taped in place. I removed the tape, and after a couple wraps of paper, I got to the point where the PT leads were soldered to the enamel wires making up the secondary winding. After a few turns removed from the secondary, I found the point where the hair-like wire overheating and burned in half. I used a razor blade to scrape off any varnish insulation on the wire, then carefully wrapped 4-5 turns around the tinned end of the PT lead. Some very quick & careful soldering completed the connection, and the repair passed a continuity test.

Replaced the PT in the VTVM (and swapped the rectifier and filter cap for good measure), and it fired up on the first try.

These things can be repaired, they just require patience, a steady hand, and careful soldering.

[DummyLoad]

assumed you checked cables and jacks first and they are good. turn reverb level up all the way. turn volume up to where you just start hearing hum. bang on tank. if you hear the springs rattle then recovery ckt is working. if you don't, it's likely driver ckt or the tank. i have yet to diagnose a defective reverb transformer - just dead tubes, caps, resistors and 1 tank that i was able to repair. i don't do much service work, mainly just builds and experimentation. thought i share some limited knowledge and experience.

peace.

--DL

[eleventeen]

"If the tank is already shot, there's no harm in attempting to repair the output side. You can't break it any worse than it is now.

Right on the money. Need very low heat soldering iron and be quick and gentle. I've repaired a few rev tanks. It's usually the transducer wires that broke away from the RCA in/out jacks, but I have also resoldered to the tiny little terminals on the transducer coil. I think I've fixed 3 out of 4 or 4 out of 5. Those tanks are a lot more rugged than one might think.