How old is my Triplett 310?

[BeBuLamar]

I just bought this Triplett 310 VOM today at an estate sales for $7.50. It's full functioning and reasonably accurate. It reads a bit low on both AC and DC voltages. I wonder if there is a pot for calibration? Also how old is it? I know the first one was made in 1955 and they still make them today.

[coppercone2]

well I got one of those from the 80's but I destroyed the acrylic knob. I have been meaning to polish out a groove in there so I can glue on something, or to find a replacement.

Check for leakage from the 12V battery in there for Ohmmeter mode.

And its adjusted by replacing resistors IIRC. That thing is pretty stable and small, I don't think I saw any trimmers in mine (but its for Bell)

Yours has a knob on the bottom, mine has more of a watch dial.

I think I have a 318 though. Maybe you can just get parts for that still, I never looked. I had a fun time polishing it with tooth paste lol


It has a potentiometer for ohms, but I don't think you can do anything with the voltage dividers other then replacing resistors


https://www.parts-express.com/pedocs/manuals/391-040-triplett-310-manual.pdf

[coromonadalix]

your needle mechanical zero  seems wrong for a start

and if this attached file     schematic / brochure is right you  have only 1  trimpot in it ....

and it has an 1977  stamp  on it   it give some insight ...

[Shock]

By the look of it 70s or early 80s is about right.

Edit:
If they didn't update the model at all looking inside will give you a rough date code if you can find a dated component or age them. Don't always jump straight to calibration to fix things. If it has a sticky or problematic movement, non zeroed or a drifted component, you will have just wasted your time and possibly made it harder to pinpoint.

[schmitt trigger]

Does it read low on ALL of the AC and DC ranges?

If so…I would like to think that then it is possible that the movement itself has a flaw.

Keep us posted on what you find.