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Thread: Vibroking reverb problems

  1. #1
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    Vibroking reverb problems

    My Vibroking reverb is dead! you can hear the return is working by shaking the reverb tank but it does not seem to get any signal input?
    I have changed the standard things: one cap & one resistor, the 6v6 the reverb driver transformer ,checked the valves, still no input to the reverb tank? What am i missing?
    As the "Spencer Davis group" sang a long time ago, "Somebody help me please".

    Vibrochamp.

  2. #2
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    Re: Vibroking reverb problems

    It is probibly the input side of tank itself. since you can hear the springs crash when you shake or tap the tank hard then the recovery amp and the output side of the tank are ok. the fastest way to check the input side is with ohm meter.
    unplug the send side RCA cable from the reat of the amp and measure with the meter, you should get a low reading, but a reading none the less. If you do not, then as is the case most times one of the small wires coming off of the pans input RCA jack has come off and needs to be resoldered.
    At time these small wires will break off at the transducer at the other end of these small wires.
    Some of the new pans have slip on connectors at the transducer, so removing the slip on connector and soldering right to the slip tabs solves the problem, if it is not this new type and the wire goes right use to go right into the transducer, your done, and its time for a new pan.
    while you are in their it pays to take some time to get some gel type super glue and glue down the transducer to the iron core its mounted on, as even in new pans these transducers are loose on the core which reduces their effectiveness and results in poor reverb tone and drive.
    It also pays once you fix the pan or get a new one to get some clear silicone glue and place a good dab on each end of these small wires so vibration does not do them in again, even if you have transducers with slip on connectors do this and your pan will be bullet proof!

  3. #3
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    Re: Vibroking reverb problems

    Also your input side rca cable could be open so you should resistance check that also end to end.

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    Re: Vibroking reverb problems

    OK Steve will do.
    Let you know how it goes.
    Cheers.

  5. #5
    Forum Member cdw2000's Avatar
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    Re: Vibroking reverb problems

    Quote Originally Posted by steve25 View Post
    At time these small wires will break off at the transducer at the other end of these small wires ... [If] the wire goes right into the transducer, your done, and its time for a new pan.
    Not necessarily. When I was a poor college student, I got a very good deal on a Crate 25R (remember when Crates really looked like wooden shipping crates?) because the reverb didn't work. I isolated the problem to one of the transducers in the reverb pan, so I took the reverb pan apart and carefully peeled back the covering on the transducer, which looked like a tiny transformer. I found the point where the lead had broken from the hair-thin magnet wire and managed to re-solder it. I re-wrapped it and put it all back together. The reverb worked great the whole time I had the amp.

    So if you want to try some micro-surgery you can repair these.

    I hate just throwing things away. If there is any chance in repairing something, I will give it a try.
    "Time is an illusion, lunchtime doubly so" -- Douglas Adams
    "If something has a 1 in a million chance of occurring, 9 times out of 10 it will happen" -- Terry Pratchett

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    Re: Vibroking reverb problems

    Did the tests, reverb tank is ok(tried it on my Twin)
    I wired the reverb send output from the amp to my monitor/headphone amp and there is no send signal coming from this part of the curcuit in the amp. So what could be the next step guys?
    Cheers, Vibrochamp.

  7. #7
    Forum Member cdw2000's Avatar
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    Re: Vibroking reverb problems

    Looking at the schematic, the signal splits right after the input jacks. The dry path goes through V1B and the reverb path goes through V1A.

    Have you tried changing out V1? It is possible that 1/2 of the 12AX7 is gone while the other half is still functioning. I would also check out the circuitry around V1A (pins 1, 2, and 3).

    In case you don't have the schematic, Fender very graciously has a downloadable version:

    http://www.fender.com/support/amp_sc..._Schematic.pdf
    "Time is an illusion, lunchtime doubly so" -- Douglas Adams
    "If something has a 1 in a million chance of occurring, 9 times out of 10 it will happen" -- Terry Pratchett

  8. #8
    Forum Member Mesotech's Avatar
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    Re: Vibroking reverb problems

    There doesn't appear to be much to that area of the schematic. There's only a few caps, resistors, a pot (dwell), choke, and 2 tubes (V1a and V3) that affect the reverb send. If you've already checked the tubes, I would next test the Dwell pot to ensure it works properly and doesn't have an open or bad solder joint. Then check the voltages for X, Y, and Z to ensure the power supply is putting out what it should. Obviously my first thought would be the tubes. Swapping V1 for V4 would be a real good swap because if V1a is bad but V1b is good, the whole amp will die with the V1 tube in V4's slot. Swapping V1 with V2 might not yield any noticable difference since V2 is also used on the reverb recovery and if you're simply testing to see if swapping those tubes causes the reverb to start working again, it would still appear broken with V1 in V2's slot. V3 is the 6v6 so there's nothing else to swap it with in this amp (but you've already replaced this one and didn't fix anything).
    POO DAT!!!

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    Re: Vibroking reverb problems

    tap pin 5 of the 6v6 with with a small metal screwdriver and with the verb up all they way, if you hear a click or a pop than the problem lies before the 6v6.
    You do have plate voltage on pin 3 of the 6v6, aout 460 right?

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    Re: Vibroking reverb problems

    OK. Will do.
    Thank God for the Fender forum!
    Cheers everybody.

  11. #11
    Forum Member ziess's Avatar
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    Re: Vibroking reverb problems

    Could be a bad tube socket. I had an issue recently with an amp I fixed that turned out to be that.
    Where are you anyway?

    Tommy.

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    Re: Vibroking reverb problems

    Im in Norway.
    Will check out all the tips you guys have given me.
    Full report tomorrow.
    Cheers, G.

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    Re: Vibroking reverb problems

    Sorry chaps, iv e been sick the last few days.
    Do some tests at the weekend.
    Keep your help coming.
    Cheers.
    G.

  14. #14
    Forum Member ziess's Avatar
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    Re: Vibroking reverb problems

    Is it under warranty?

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