The Precise 9071 VTVM, Part 1: Observations
Wednesday, August 19, 2026 at 09:36:28
Since I love meters, here’s another one…this one didn’t come from a hamfest, but came with the eBay tax attached. I was able to get it for a lot less than a similar EICO 249 would sell for, so there is that.
Much like the EICO 249, this meter features your standard measurement options, as well as the giant meter face. This example is dirty, but in decent shape for the age.
The back of the unit is nothing special. The cord simply runs out of a hole and is strain-relieved inside.
Inside, we have a wiring nest.
There’s our friends, those blue carbon film resistors. Jay Hooks makes an appearance as well, although it’s done in a much nicer way than the EICO 950A was.
The control potentiometers are well blackened, as if this device spent some time in a wet or harsh environment.
Here’s our old friend, the RCA battery for the ohms function. This thing hasn’t been touched for a long time.
And some cool old C-D capacitors. Everything in here is disc.
I’m not sure if this unit was a kit, or if it was a factory build. Everything is covered with spaghetti, so if it was a kit build it was well done. I do have another example of this unit on the way as a donor, so we’ll see if it’s built in the same manner. I will say that it has some parts that have been replaced over the years, so who knows.
What makes this unit unusual? This one has 4 tubes.
It has these tubes:
6X5 as the power rectifier - no selenium here!
6SN7 as the input isolator/amplifier
6AL5 as the measured signal rectifier
0A2 as a voltage regulator
That last one is the odd man out. This device has a regulated power supply, so it should be somewhat immune to line frequency variations - something other VTVMs of the era had trouble with.
Does it work?
Sort of.
I did some quick checks on the unit, the filter capacitor didn’t seem shorted, so I plugged it in raw. The tubes have a lot of hours on them, but they lit - I didn’t see the voltage regulator fire so something is wrong in there. It does measure, but it’s way off and started to drift all over in the few minutes I had it up. So, it works, but is not operable as a voltmeter. But it does work, so it’s a good restore candidate - and it will have it’s time on the bench at some point. Stay tuned!
Next part of this series: Coming sometime.