Universal Atomics CDV700 Troubleshooting

[CollapsedNut]

Hello. I like playing with things and my latest venture is this

I didn't figure it would work without some repair so I'm not disappointed. I'm by no means an electronics expert but I can hold my own in testing and replacing components, when I know what I'm looking for haha. I put batteries in, set the switch to x10, placed the tube with window open over the check source and got nothing on the gauge. Moved the switch down to x1 and still nothing. I even tried tapping on the meter to see if it wold work but nothing! Bigger hammer needed obviously. Kidding. I gave it all a good once over and didn't see any obvious issues like a bad capacitor or corroded connections. I can hear a faint high pitch noise that changes slightly when the switch is moved to different selections.


Just did a quick test where the battery leads meet the board. I get 3.2v on both red and green wires when using the ground circled in red. I get 4.8v on both red and green wires when using the ground marked in blue.



I figured I could test the meter gauge by seeing if it's supply voltage increased with the tube over the check source. I get a fairly steady 2.3v on the gauge connections regardless of if the tube is over the check source or not and switch position has no effect. It will vary from 2v to 2.4v for seemingly no reason however. This seems odd to me, but I also think a gauge like this works more on amperage than voltage so this test may mean nothing.


That's about as far as I've gotten. I figured I might try to check the tubes voltage more to see if it had ANY vs an exact reading and promptly got shocked so I backed away from that test for now until I know more about what I'm dealing with. But I guess it has voltage hahahaha.


Any advise for testing procedures here? Thanks!

[SloGlo]

yins due understand that yew got an antiquity, write?
hoe kay, yue may find help wit sum info awn this hear sight;
http://www.minionreport.net/radmanuals.html

[61nomad]

Maybe the check source has decayed away and is not strong enough to move the needle.  Does it say what the isotope is?  Half-life?

[atomicarcheologist]

If you need a check source for those old Civil Defense meters, get some old school Fiestaware.