An EICO 249 VTVM, Part 11: Testing the rebuild.
Thursday, August 13, 2026 at 07:56:13
As I’m primarily interested in this device as a DC meter, I did a quick calibration on that section. Before that, I greased the detents on the switches and ran a bit of deoxit on the metal portions of the wafers.
This device is supposed to have a 1MΩ resistor in line with the probe, all in a coaxial cable shell. I do not have that, so this may be a little off. I believe the probe for the EICO 242 may work, so we’ll see.
The manual suggests calibrating the DC range at 3.1V, or “the voltage from two fresh flashlight batteries in series.” Ok, sure. Let’s set the power supply at 3.1VDC, measure it with a known good digital voltmeter, and dial it in using the control on the side.
That’s pretty good for an analog meter. If I replaced that cal pot with a 10-turn, I could probably dial it in even better, but that’s not necessarily worth it. I’m happy with the result.
I did check the AC briefly, it does work, but I need to get some other devices set up to do that. However, the meter works, it is as accurate as you can get with an analog meter, and it’s ready to go into service.
Next post is the wrapup, stay tuned!
Next part of this series: https://wereboar.com … -and-final-thoughts/
Previous part of this series: https://wereboar.com … ets-test-some-parts/
Wrapup and final thoughts: https://wereboar.com … -and-final-thoughts/
References
Manual set: https://wereboar.com … with%20schematic.zip
Youtube Playlist: https://www.youtube. … k&list=PLbV6LYdZISZI
The playlist has more videos scheduled for much later, there are several months difference between here and YouTube.