Fixing an ammeter

Discussion in 'Supporting Physics' started by Korinna, Feb 2, 2018.

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  1. Hi there,
    I have a SATZ ZA101 School ammeter' which isn't working. When I changed the battery the display is coming up with four vertical lines or flashing 'E'. I can't find any info online about how to fix it so was wondering if anyone here could help?
     
  2. Not familiar with this make, but I wondered if it might have an internal fuse. That used to flummox me on our multimeters
     
  3. Not seen that before. Never had one apart yet but they eat batteries if left on. They really need an auto off.
     
  4. Dod

    Dod

    Methinks there will be an internal fuse to prevent the electric blue smoke and flashes getting out when in the little dears give it too many amps.
     
  5. If there is it is very well hidden. They are rated 10A and I think they rely on no school power supply achieving that.
     
  6. Dod

    Dod

    In our place they can blow 10A fuses in the multimeters :(
     
  7. what power supplies do you have?

    They blow the small fuses in the multimeters, I just change them for resettables. Never had anybody blow the 10A. We can only get 8 amps from our most powerful bench supplies.
     
  8. I'd open it up & see if there's anything obvious, if not then the great garbage disposal in the sky calls! Just in case: the screws are under the rubber feet (peel off) - just like the timers. With the timers I've managed to fix a few (wires come loose, just needed re-soldering) or replaced the activating buttons/switches - but have only had one of the ammeters apart & it was a physical problem (switch had slipped) rather than electrical......sorry, can't remember if I saw a fuse in there or not
     
  9. I looked this morning, there is no fuse.
     
  10. Dod

    Dod

    Common ordinary orange and brown ended Unilab ones, don't know how they manage it myself but they manage it.
     
  11. I only have one unilab orange ps at school, it is my preproom bench supply. That's only 4 amps. It is model 022.104
     
  12. More information, please. I put the 2A fuses external to the case on our Flukes, which speeds things up somewhat. Now the little darlings just smash the fuseholder off......
     
  13. bourns multifuse MF-R020 0.2A

    Rapid 26-4602

    just solder one in to replace of the 200mA glass fuse.
     
    mike wilson likes this.
  14. The 2A ones are a bit big but might go in. Worth a punt, anyway. Many thanks.
     
  15. Dod

    Dod

    Ours are 022 314 rated at 6A but they still manage 10A fuses in meters
     
  16. This is a good idea, although looking at the trip times, some of the multifuses might be a little too slow for as much protection as a normal glass fuse.
    How well do you find it works, and what kind of meters do you put them in? :)

    (also, the rapid ones you linked are discontinued, but here's a replacement range: https://www.rapidonline.com/bourns-multifuse-mf-r-series-ptc-resettable-fuses-64685 )
     
  17. I put them in all the multimeters we have, different ratings for different multimeters, we have a lot of the small cheap ones and then around ten of the larger display types.