|The Utility Solid State Voltmeter IM-17
on the market in 1967 and was produced until 1977. In 1979 the IM-17
was replaced by the IM-5217
and was produced until 1987. There is only minor differences between
the two and it is mostly a matter of look and feel.
have slightly modified my IM-17.
have replaced the fixed test probes with standard 4mm test jacks to
make it more versatile like modern Multimeters. The DC-probe had a
1Mohm resistor built-in so I had to incorporate a replacement for it
inside the IM-17. I have
modified my IM-18 in a similar way.
Furthermore I have replaced the 8.4 volt mercury battery with a
volt alkaline battery. I have also incorporated a battery check switch,
to be able to measure the actual voltage of the 9V battery. It turns
the meter to be a simple voltmeter, calibrated for 10V full scale for
direct reading of the battery state.
schematic of the original unmodified IM-17
schematic of the modified IM-17