The Utility Solid State Voltmeter IM-17 came 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.


I have slightly modified my IM-17. I 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 standard 9 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.

The schematic of the original unmodified IM-17



The schematic of the modified IM-17