Changing a Multimeter setting from a x10 to a rx1

Discussion in 'The Projects Forum' started by Mr.Piccolo22, Feb 24, 2012.

  1. Mr.Piccolo22

    Thread Starter New Member

    Oct 27, 2009
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    I am beginner at electronics and I tried searching the forum to see if this was posted already, so I am sorry if it was...

    I purchased a analog multimeter that I wanted to use for a project. However I need to switch the lowest setting from Rx10 setting to a Rx1. Is there a way I can switch out a couple of resistors and have it read the RX1 setting?

    The Meter is a M1016B Commercial Electric.

    I attached a picture of the PC board.

    Thanks for any help.

    Mr.P
     
  2. BSomer

    Member

    Dec 28, 2011
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    It doesn't have a switch on the front for that option? Seems a little strange.
     
  3. Mr.Piccolo22

    Thread Starter New Member

    Oct 27, 2009
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    That would have made it easy, but it didn't.
     
  4. MrChips

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    Oct 2, 2009
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    Your meter is most likely a very inexpensive one. Can you show a photo of the front of the meter? Digital meters have also come down in price. You can buy a digital meter on sale for under $10. Don't bother to mess with the one you already have.
     
  5. BSomer

    Member

    Dec 28, 2011
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    Well without seeing a schematic or the traces I am at a loss as to where to go on it. Since it looks like there are only resistors, diodes, and maybe a couple of caps it should be as simple as changing a resistor or two. However, doing so may screw with the voltage read out as well.
     
  6. Mr.Piccolo22

    Thread Starter New Member

    Oct 27, 2009
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    It is an inexpensive unit, however I need the analog to see the sweeping motion and the digital wouldn't show it as quickly. As far as the rest of the of the meter I really don't need to test anything else but the Rx1 ohm setting.
     
  7. MrChips

    Moderator

    Oct 2, 2009
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    It would appear that your meter is already damaged. Why is there a big blob of solder on the switch wiper contacts?
     
  8. Mr.Piccolo22

    Thread Starter New Member

    Oct 27, 2009
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    I did that to to permanently keep it in the Rx10 ohm setting, which I want to switch to the Rx1. Plus it had to some how I needed to make the points of connections that I removed the sweeper contact. I didn't need the rest of the box because I am going to to repackage three meters into one project box.
     
  9. BSomer

    Member

    Dec 28, 2011
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    That big blob of solder could be a cheap form of a mechanical stop for the selector switch.

    edit... nevermind.
     
  10. #12

    Expert

    Nov 30, 2010
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    We're going to get nowhere without a schematic. This is like asking what the gear ratio is in a transmission by showing a photo of a car.
     
  11. Ron H

    AAC Fanatic!

    Apr 14, 2005
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    See the attached schematic and explanation.
     
    Last edited: Feb 26, 2012
  12. Mr.Piccolo22

    Thread Starter New Member

    Oct 27, 2009
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    Ron,

    Thank you for the diagram. I am going to print it up and review it and look up a lot of terms up and get an understanding of what you gave me (still very new and trying to learn). If I have any questions do you mind if I send you pm?

    Thanks.

    Mr.P
     
  13. CDRIVE

    Senior Member

    Jul 1, 2008
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    Actually, this can be done (believe it or not) without a schematic, instruments, or even knowledge of the meter movement's FS E or I spec,... or it's internal resistance.
     
  14. Ron H

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    Thank you so much for the very informative post.:rolleyes:
     
  15. Ron H

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    No one else benefits from PMs. Let's keep any exchanges here on the forum.
     
  16. CDRIVE

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    Forgive me, it wasn't meant as a definitive. I was late for my Saturday happy hour. Will give specifics later. Sent from my bar phone
     
  17. Ron H

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    Ah, I agree with your priorities.:D
     
  18. CDRIVE

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    Jul 1, 2008
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    Ron, I looked at your schematic and read your description and theory of operation. All looked good and accurate except for one thing and that one thing changes things considerably. Mr.Piccolo said that he wants an R x 1 scale but the lowest range on his meter is R x 10. That would make mid scale = 100Ω, not 10Ω. That would also mean that currently Rsh= 100Ω, not 10Ω. So, it would follow that an R x 1 scale would require Rsh= 10Ω. not 1Ω. It would then follow that FS would require 150mA, not 1.5A. To restate.. Did you mean to provide an R x 0.1 scale or did I spend too much time at the watering hole? The latter would not be my first time. :D

    Chris
     
  19. Ron H

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    Geez, Chris, I'm a little embarrassed. I just assumed that the lowest range would have the actual resistor values on the scale. Duhhh... I didn't even think about having to multiply by 10. Brain fart, I guess.
    So you're correct. I think.:rolleyes: I will revise my attachment and repost it.
    What was the method you referred to in post #13?
     
  20. #12

    Expert

    Nov 30, 2010
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    Also waiting for the method mentioned in post #13!
     
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