Home › Forums › Help/Technical Questions › Classic DMM temperamental delay time pot

Viewing 8 posts - 1 through 8 (of 8 total)
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  • October 2, 2009 at 10:13 am #79071
    archaos
    Participant

    Hi guys,

    I have purchased a DMM (with MN3005 chips) @ analogman in last Sept., & I know issues with the delay pot.
    Indeed, the delay time doesn’t change when I turn clockwise/counterclocwise the knob.
    The delay setting remains on the longest delay time.
    However, if I keep the pot pulled up a little, it works, the delay time changes “correctly”.
    I guess this pot is deficient.
    So, here are my questions :

    – is it possible to change this pot myself ? I mean does changing it require any trim pot adjustments ?
    – where can I find a similar component as far as it seems hard to find ?

    Thanx for your answers.

    October 2, 2009 at 10:41 am #101984
    The EH Man
    Moderator

    I’d remove the back and resolder the pot first as that may take care of your problem.

    If not, the pot may need to be replaced or at the very least, opened up and the wiper contact readjusted.

    October 2, 2009 at 11:59 am #101987
    archaos
    Participant

    Wow, thanx for that quick answer !

    Apparently the pot is well soldered, I think it’ll be necessary to swap it, in so far as it seems very hard to open it up to readjust the wiper contact.
    Where can I find this kind of pot (B 100k) with a knurled split shaft ?

    October 2, 2009 at 12:05 pm #101988
    The EH Man
    Moderator

    Being that this is the older big box unit I’ll bet the pot was hit/stepped on and has just opened up a bit. If you look at the pot you’ll probably find that the casing just needs tightened up. Crimp it back down with some pliers and you’ll be fine.

    October 2, 2009 at 12:37 pm #101989
    archaos
    Participant

    Well, I must say it’s very well-spotted.
    Your tip sticks completely to my matter. I shall try to tighten up the casing tonight @ home, shall let you know.

    Thanx !

    October 2, 2009 at 6:02 pm #101996
    archaos
    Participant

    Arghh, impossible to make this damned pot work correctly.
    Have tried the following tip : have removed the back, have tightened up the casing, but it gives nothing new.
    The issue remains, therefore I guess I’ll have to change the pot now.
    Where can I find a similar one knowing it has right angled PC mount vertical terminals ?

    October 9, 2009 at 10:35 am #102114
    archaos
    Participant

    Any answer from an administrator ?

    I’ve contacted info@ehx.com twice in one week, & haven’t got any answer, too :-(

    October 18, 2009 at 4:46 pm #102397
    archaos
    Participant

    A big THANX to Mike from analogman.com who sent me an identical replacement pot !

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