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Vintage Test Gear and Workshop Equipment For discussions about vintage test gear and workshop equipment such as coil winders. |
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29th Aug 2019, 10:30 am | #1 |
Dekatron
Join Date: Jan 2004
Location: Newcastle upon Tyne, Tyne & Wear, UK.
Posts: 8,194
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Maplin Gold DVM M 510 EC
Hi Folks, has anyone details of circuits of this meter, which uses the Intersil ICL7106 CPL chip.
It reads about 30% of what it should on both AC and Dc volts, but fine on Ohms; current ranges not checked but new PP3 fitted Thanks, Ed |
29th Aug 2019, 11:02 am | #2 |
Dekatron
Join Date: Jun 2016
Location: London, UK.
Posts: 3,687
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Re: Maplin Gold DVM M 510 EC
Look for any leaky electrolytic caps. That's usually what knackers the Flukes around that era. Also check voltage dividers up front (just plug another DMM on ohms mode into the volts when it's off and check it reads around 10 meg). Also look for damage to the main switch.
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29th Aug 2019, 2:20 pm | #3 |
Tetrode
Join Date: Feb 2007
Location: Liverpool, Merseyside, UK.
Posts: 99
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Re: Maplin Gold DVM M 510 EC
In the absence of the actual multimeter's circuit diagram, the circuits provided in the ICL7106 datasheet and application notes may help:
https://www.renesas.com/eu/en/www/do...106-07-07s.pdf https://www.renesas.com/eu/en/www/do...note/an046.pdf |
29th Aug 2019, 8:32 pm | #4 |
Dekatron
Join Date: Jan 2004
Location: Newcastle upon Tyne, Tyne & Wear, UK.
Posts: 8,194
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Re: Maplin Gold DVM M 510 EC
Thanks guys, this one looks pretty pristine inside,clean and no signs of overheating, so it needs a closer look.
Ed |
29th Aug 2019, 8:49 pm | #5 |
Rest in Peace
Join Date: Feb 2004
Location: Hexham, Northumberland, UK.
Posts: 2,234
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Re: Maplin Gold DVM M 510 EC
Has the 7106 got a reference voltage input on one of the pins? could be worth checking that is correct if it has. I would have thought that the ohms range would be affected at the same time though. Maybe the presumably very high value input divider resistor chain has drifted high. With some DVMs I have seen copper track creepage on the PCB contact pads under the rotary switch. Worth a check if you are brave enough to dismantle the switch what with the usual springs/tiny ball bearings etc!
Alan. |