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Thread: AVO Two Panel Tester

  1. #1
    Join Date: Jan 2013

    Location: Bristol

    Posts: 6,035
    I'm Justin.

    Default AVO Two Panel Tester

    Just dug this out.

    Tried to test a 45. Basically it doesn't work.

    It powers up fine. Heater voltage set to 2.5V and looking at the filament that looks about right in terms of glow for a 45. Set 4V and it's too bright. I therefore believe it is supplying about the right heater voltage.

    Anode is set to 100. Select anode set to normal. Set mA/V switch is set to mA/V marking.

    With these settings it should be possible to set the meter to read zero. However, that's impossible and the lowest value I can back it off to is 4.8 mA/V. But then it slowly rises see 2nd pic.

    The Philco 45 is working and known to be good. The switch settings for a 45 are correct according to the AVO Data Manual.

    Conclusion is it is bust. I have known that for a long time.

    Anyone on the forum know how to fix these meters?

    Mod fix the title to AVO?

    Cheers.


  2. #2
    Join Date: Oct 2012

    Location: The Black Country

    Posts: 5,133
    I'm Alan.

    Default

    I could take a look at it for you Justin old boy.
    I like a challenge

  3. #3
    Join Date: Jan 2013

    Location: Bristol

    Posts: 6,035
    I'm Justin.

    Default

    Alan like the sound of that.

    Will PM at some stage over the weekend.

  4. #4
    Join Date: Jan 2013

    Location: Bristol

    Posts: 6,035
    I'm Justin.

    Default

    Just spotted in a computer repair shop in Clifton...

    Retro cool.

  5. #5
    Join Date: Feb 2013

    Location: scotland

    Posts: 333
    I'm alan.

    Default

    A O Tester....?

    What....... Tests Amps, Ohms but no Volts.

  6. #6
    Join Date: Jan 2013

    Location: Bristol

    Posts: 6,035
    I'm Justin.

    Default

    A few internal shots.

    Couple of caps which I suspect are from around 1938.

    The main concern seems to be the state of the large tranny.

    Alan please take a quick look. I don't know whether that looks repairable. Don't want to send it on if it looks doubtful. But we do know that large tranny supplies about the right heater voltage (amazingly).


  7. #7
    Join Date: Jan 2013

    Location: Bristol

    Posts: 6,035
    I'm Justin.

    Default

    Some more...
    Last edited by User211; 08-07-2019 at 11:05.

  8. #8
    Join Date: Oct 2012

    Location: The Black Country

    Posts: 5,133
    I'm Alan.

    Default

    It looks old, it is old, with insulation materials to match.
    I will definitely replace the two wax capacitors but I doubt there will be a problem with anything else.

  9. #9
    Join Date: Jan 2013

    Location: Bristol

    Posts: 6,035
    I'm Justin.

    Default

    OK will try and post out tomorrow.

    The wiring insulation is shot in places. But I can't see anywhere where it would cause an actual problem. It may be prudent to correct the obvious issues where they can be seen.

    I think the issues it has are deeper rooted than the two caps and wiring, so enjoy trying to suss it out
    Last edited by User211; 08-07-2019 at 12:38.

  10. #10
    Join Date: Oct 2012

    Location: The Black Country

    Posts: 5,133
    I'm Alan.

    Default

    Does the unit have a 4 pin socket suitable for 211 valves?
    If not have you a spare 4 pin socket you could send as well?

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