Reverb Tank Woes

Discussion in 'Tech-Talk' started by T Bone Slort, May 23, 2021.

  1. T Bone Slort

    T Bone Slort "Was you ever bit by a dead bee?" Silver Member

    Age:
    73
    Messages:
    9,456
    Joined:
    Jan 7, 2014
    Location:
    Gibsons British Columbia
    When it comes to electronic stuff I'm out of my element.
    The reverb in the recently purchased Fender 112 Deluxe Plus amp is not functioning and I'm trying to track down the cause.

    The tank is a US Accutronics 8EB2C1B with an input impedance of 800 Ohms and an output of 2575 Ohms.
    When I put an Ohm meter on the input jack with the meter on the 2K scale, I get a reading of 4.63 and 0 on the output jack.
    What does this indicate... a faulty pot maybe or this normal?

    I did try an Accutronic long tank that I had and I did get some reverb but the input and out put of that tank was different and I got a bunch of feed back.

    The original tank seems to be intact with no loose or broken wires.
    Also I'm not getting continuity between the input and output within the tank (see yellow ovals in photo) but everywhere else.

    Any guidance would be appreciated.

    IMG_0628a copy.png
     
  2. Wound_Up

    Wound_Up Custom Title Silver Member

    Messages:
    3,589
    Joined:
    Jan 23, 2020
    Location:
    NW LA
    You can get a new one for about $20 USD. I'd just order a new one.
     
  3. Gedster

    Gedster Strat-Talker

    Age:
    59
    Messages:
    147
    Joined:
    May 11, 2021
    Location:
    NSW Australia
    At this point in your diagnosis your just looking for continuity in the circuit, rather than trying to measure Impedance which only becomes relevant once you have an AC current (your signal) moving through it.

    Set your meter to buzz when it detects 0 Ohms, follow the signal path and look for where it breaks down. So, put one probe on the + terminal of the input jack and just trace the path all the way through to the + terminal of the output jack. If you still haven’t found the issue, check to make sure you have 0 ohms between the input terminal and earth. That should tell you where the problem is.

    Good luck!
     
    Andrew Wasson and T Bone Slort like this.
  4. Wound_Up

    Wound_Up Custom Title Silver Member

    Messages:
    3,589
    Joined:
    Jan 23, 2020
    Location:
    NW LA
    If you wanted to modify the specs on your tank, now would be the time. If you want long decay or short, you can order those instead of the medium decay that you have currently. This is a long decay tank, 8eb3c1b


    http://rover.ebay.com/rover/1/711-5...0001&campid=5338148356&icep_item=162782505407

    I replaced the 2 spring tank in my Stage Right 15w combo with the tank you have currently, except I got the MOD tank since it has permanent connections inside where the accutronics uses a fastener at the same location. Supposed to allow less noise in or something. MOD talks about it in a bunch of their ads and things.

    If you're looking more for help diagnosing the issue, I apologize. I have no idea what to do there except replace it lol
     
    T Bone Slort likes this.
  5. T Bone Slort

    T Bone Slort "Was you ever bit by a dead bee?" Silver Member

    Age:
    73
    Messages:
    9,456
    Joined:
    Jan 7, 2014
    Location:
    Gibsons British Columbia
    I guess the easy rout is to replace the tank but before I do I'd like to know if the tank is defective or is the circuit to the tank is faulty?
    I saw a Youtube video where they measured the Ohms on the input & output jacks RCA jacks coming out of the tank. They got a reading on one end and not the other. I took my reading of the RCA jacks coming out of the amp.
    I got a 4.63 reading on the 2K Ohm scale on one jack and non on the other. I also had no continuity reading between the the two jacks going back to the amp which to me indicates the fault is in the amp, pot or other...
    But I don't have a good grasp on such stuff so I'm reluctant to just get another tank.
     
  6. fezz parka

    fezz parka fezz parka

    Age:
    63
    Messages:
    33,019
    Joined:
    Apr 21, 2011
    Location:
    Nunyo, BZ
    Transformer is pooched.
     
    Electgumbo likes this.
  7. T Bone Slort

    T Bone Slort "Was you ever bit by a dead bee?" Silver Member

    Age:
    73
    Messages:
    9,456
    Joined:
    Jan 7, 2014
    Location:
    Gibsons British Columbia
    :eek::eek::eek::eek:

    Oh well the rest of the amp works fine, good thing I have two reverbs on my board :)
     
  8. Deafsoundguy

    Deafsoundguy CERTIFIED HACK Silver Member

    Age:
    63
    Messages:
    1,727
    Joined:
    Mar 6, 2020
    Location:
    Area 51
    T-Bone, make sure you try replacing the RCA cables, and thoroughly clean ALL jacks, especially the RCA jacks on the tank. I’ve seen that problem before and with my newest tube amp, within 2 months the verb stopped working and it was not one but BOTH the issues I suggest (cables and jack connection integrity). I’ve seen many brand new electronics come with perfect looking jacks and yet when they make that stuff sometimes there’s some sort of film left over from the manufacturing process and that film impedes signal. This also happened to my Acoustasonic- it was cutting out a lot, and it was nothing more than cleaning the brand new jack on the inside of the guitar! No problems since!

    I find it kinda hard to believe the tank itself is messed up. Could be but rare. I’d guess if it’s not a dirty connection or bad cable it would be the driver stage feeding into the tank.

    Next one - absolutely can’t remember but I “think “ the tank has small transformers in it ( maybe not) and if so, that’s a reason why you won’t get continuity. Transformers pass AC (power or musical signal) but do not pass DC or your multimeter testing voltage. Neither do capacitors, they are used (in this respect - non polarized) to pass (AC) signals between amp stages yet not allow DC. Therefore blocking things that blow up from further damaging things past that stage. Like if an IC blows up it won’t take out more IC’s down the chain. That’s called a blocking cap.

    There’s a test on this later
     
    Wound_Up and T Bone Slort like this.
  9. Meghans Dad

    Meghans Dad Strat-Talker Gold Supporting Member

    Age:
    67
    Messages:
    351
    Joined:
    Jan 24, 2021
    Location:
    So. Cal.
    If your getting no resistance on the tanks output, there is a short in that side of it. if there is no circuit (OL) than one of the wires leading to or from the coil on that side is broken. this is what most often happens. remember, those little wires are always vibrating. I tried to fix one with that issue once and came to realize that my soldering skills were not up to the minutia of the task and just replaced it.
     
    T Bone Slort likes this.
  10. T Bone Slort

    T Bone Slort "Was you ever bit by a dead bee?" Silver Member

    Age:
    73
    Messages:
    9,456
    Joined:
    Jan 7, 2014
    Location:
    Gibsons British Columbia
    That was the first thing I checked.
    In the photo I attached, you can see that I took the connectors off and got no continuity between the input and output pins but I do get continuity between the bars that hold the springs.
    This leads me to believe that the one or both of the little coils are pooched.
    At this point I just want to confirm that the pot and the circuit to the tank is good before ordering a new tank.
    Of course @fezz parka has thrown me a curveball by suggesting that my transformer is shot.

    I should have paid more attention in Electric Shop in high school back in the early 60's rather than fooling around with hopped up cars.
     
    Last edited: May 25, 2021
  11. Jimi Lightning

    Jimi Lightning Most Honored Senior Member

    Messages:
    6,286
    Joined:
    Dec 21, 2016
    Location:
    Ontario, Canada
  12. T Bone Slort

    T Bone Slort "Was you ever bit by a dead bee?" Silver Member

    Age:
    73
    Messages:
    9,456
    Joined:
    Jan 7, 2014
    Location:
    Gibsons British Columbia
    Now I'm totally confused, I guess I should take the chassis out and have a look inside...not that I'll know what to look for unless there is something obvious.
     
  13. T Bone Slort

    T Bone Slort "Was you ever bit by a dead bee?" Silver Member

    Age:
    73
    Messages:
    9,456
    Joined:
    Jan 7, 2014
    Location:
    Gibsons British Columbia
  14. 4wotitswurth

    4wotitswurth Strat-Talker

    Age:
    66
    Messages:
    106
    Joined:
    Oct 31, 2020
    Location:
    Texas
    If I’m not mistaken the input side is simply a coil (transducer) wired to the input plug. And the output is the same. You should see continuity at the input connector socket and continuity at the output connector socket, that shows both coils have continuity. The reading would be the resistance of the coil you’re looking at. As said above it really is a sort of transformer configuration, two coils linked mechanically…. I think ;)
     
    Andrew Wasson and T Bone Slort like this.
  15. Antstrat

    Antstrat Dr. Stratster

    Messages:
    11,470
    Joined:
    May 6, 2019
    Location:
    Over There
    Had an issue with my reverb on my 65DRRI, it wouldn't work.

    Did the basics like cleaning the connectors, changed the reverb tube, etc. Nada.

    Pulled the tank, looked brand new and shiny, nothing visible.

    Long story short, ordered a new tank and worked like a charm.

    $30 from these guys https://www.amplifiedparts.com/
     
    soulman969, jtoomuch and T Bone Slort like this.
  16. Antstrat

    Antstrat Dr. Stratster

    Messages:
    11,470
    Joined:
    May 6, 2019
    Location:
    Over There
    oops, didn't see this post. Not the same issue that I had posted above is it? ^^^^^^^^
     
  17. T Bone Slort

    T Bone Slort "Was you ever bit by a dead bee?" Silver Member

    Age:
    73
    Messages:
    9,456
    Joined:
    Jan 7, 2014
    Location:
    Gibsons British Columbia
    That translates to $75 CND after shipping which is almost what I paid for the amp. So I want to make sure a new one will work before ordering a new one.
     
    Antstrat likes this.
  18. T Bone Slort

    T Bone Slort "Was you ever bit by a dead bee?" Silver Member

    Age:
    73
    Messages:
    9,456
    Joined:
    Jan 7, 2014
    Location:
    Gibsons British Columbia
    The amp works fine, he may have meant transducer which is in the tank and that seems to be where the fault lies.
     
    Andrew Wasson and Antstrat like this.
  19. Meghans Dad

    Meghans Dad Strat-Talker Gold Supporting Member

    Age:
    67
    Messages:
    351
    Joined:
    Jan 24, 2021
    Location:
    So. Cal.
  20. BuddhaFingas

    BuddhaFingas Senior Stratmaster

    Age:
    59
    Messages:
    1,488
    Joined:
    Feb 16, 2019
    Location:
    Chino Hills, CA
    No electrical connection between input and output. A reverb is an electromechanical device.

    You shake one end and wait for the other end to wiggle, and then for the wiggle to bounce back and forth a few times.