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    George Kaye Small Signal Tube Tester Needing Diagnosis/Repair

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    howlin' hoosier

    Posts : 33
    Join date : 2012-04-30

    George Kaye Small Signal Tube Tester Needing Diagnosis/Repair

    Post by howlin' hoosier on Tue Mar 06, 2018 7:23 pm

    I recently came into possession of a George Kaye Small Signal Tube Tester. It's not operating properly - no matter what settings are made or if there's even a tube installed in the tester the meter pegs to the right and no settings change that. I tried reaching out to George Kaye and got a few generic suggestions on how to use the tester, but after explaining that the tester made no noise until the volume got to 1 o'clock (and then some strange noises came through the built in speaker, as well as through the headphone jack) I stopped getting any responses to my emails when I asked if I could send it to his shop for diagnosis/repair.

    I'd get under the hood myself, but the knobs on the pots are on super tight - I'm afraid I'll damage a pot by using brute force to pry them off. Is anyone here familiar with the Kaye tester? Are there any good techs folks here are familiar with that I could contact to nurse the Kaye back to operating condition?
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    Peter W.

    Posts : 759
    Join date : 2016-08-07
    Location : Melrose Park, PA

    Re: George Kaye Small Signal Tube Tester Needing Diagnosis/Repair

    Post by Peter W. on Wed Mar 07, 2018 8:56 am

    Three things first:

    a) Do you have the wooden-box version or the Tolex covered version?
    b) Is there *ANY* visible damage on the top plate - evidence of a spill or some such?
    c) The symptoms display whether or not there is a tube in place - just to be clear that it does not take a tube to peg the meter?

    I expect that you do not have to remove the knobs to remove the guts from the case. From the few pictures I found, it seems to be secured from the back or sides such that if you remove some screws the entire guts will come out as one. This is typical of tube testers in many cases.

    If the knobs must be removed, there is a process:

    After making sure the knobs are not held in place by set-screws!

    Obtain heavy pack-thread or other tough, fine string.
    Obtain Liquid Wrench, Kroil, or WD40.
    Turn the device upside down and work some of the above onto the knobs so that it soaks into the shaft. Leave overnight.

    Wrap the string several times around the shaft, and tie off the two ends onto some sort of comfortable handle about 3" above the knob.
    With the string to either side of the knob, pull up on the handle.
    With some moderate force, they should come right off.

    Now with everything wide-open, look for loose parts, broken parts, shorts, open solder joints and any other physical evidence of something untoward. Report back.

    Best of luck!

    howlin' hoosier

    Posts : 33
    Join date : 2012-04-30

    Re: George Kaye Small Signal Tube Tester Needing Diagnosis/Repair

    Post by howlin' hoosier on Wed Mar 07, 2018 8:23 pm

    Mine is the "no wooden box" version. Meter pegs whether there's a tube in place or not. The tester is clean - no sign of beverage damage.

    The pots are attached to the front of the faceplate by a nut that's underneath the knobs. I don't see any sign of set screws in the knobs. I have some penetrating oil in a needle applicator that I use when I work on Lionel trains - good suggestion on turning the tester over and getting some oil into the knobs to hopefully loosen them up. There's a couple caps on the bottom of the board that test fine - hopefully there's nothing too seriously wrong.
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    Peter W.

    Posts : 759
    Join date : 2016-08-07
    Location : Melrose Park, PA

    Re: George Kaye Small Signal Tube Tester Needing Diagnosis/Repair

    Post by Peter W. on Thu Mar 08, 2018 9:54 am

    hopefully there's nothing too seriously wrong.[/quote]

    It is a funny thing, but on things that combine mechanical functions with electrical functions, I have found that the more outrageous the symptom, the more obvious (and easy) the fix. I am going to make a small bet - any Tastykake ( http://www.tastykake.com/products ) to any local Indiana specialty that this will be one of:

    a) A short due to a loose wire, loose part, or broken part.
    b) A open circuit - due to the above.
    c) A bit of debris that somehow got into the system and is causing a short.
    d) A pinched wire, or worn insulation.
    e) Or other similar (and obvious) failure, perhaps as a result of being dropped at some point.

    If none of that (meaning I lose the bet), one of the pots and/or multi-switches could also have failed internally - you might need to check their function when you can get underneath. But that is rare.

    howlin' hoosier

    Posts : 33
    Join date : 2012-04-30

    Re: George Kaye Small Signal Tube Tester Needing Diagnosis/Repair

    Post by howlin' hoosier on Wed Mar 21, 2018 6:06 pm

    After a gap in time I tried another email to Mr. Kaye - he opined that the voltage regulator in the tester was often guilty of failure. I'm going to open the tester back up and take another look-see.

    howlin' hoosier

    Posts : 33
    Join date : 2012-04-30

    Re: George Kaye Small Signal Tube Tester Needing Diagnosis/Repair

    Post by howlin' hoosier on Wed Mar 21, 2018 6:37 pm

    Found the voltage regulator mounted to a heat sink - it reads:

    51 FP
    LM2940CT
    -5.0 P+

    Out of curiosities' sake, is that a value that my local electronic supply house would have in stock? Is there a more durable drop in replacement since the original seems to be prone to give out?
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    CletusB

    Posts : 165
    Join date : 2018-02-11
    Age : 63
    Location : Trinidad & Tobago

    Re: George Kaye Small Signal Tube Tester Needing Diagnosis/Repair

    Post by CletusB on Thu Mar 22, 2018 3:25 am

    It's a 5Volt 1Amp Low Drop-out Regulator
    Carefully, see if you're getting 5V out of the device, center pin being ground

    https://www.digikey.com/product-detail/en/texas-instruments/LM2940CT-5.0-NOPB/LM2940CT-5.0-NOPB-ND/32575

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    Re: George Kaye Small Signal Tube Tester Needing Diagnosis/Repair

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