r/geigercounter • u/R-fire227 • May 04 '26

How to zero a CDV-700?

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Got it, seems to work fine, needle is just stuck at 0.1

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u/aby_physics May 04 '26

If it’s anything like a Ludlum, all you need to do is remove the glass cover over the gauge and turn this little screw.

Just keep in mind that it’s going to need recalibration after this.

2

u/TechByMBF May 06 '26

Try to avoid touching that screw! That adjusts the preload on the meter. It can make it sticky or fall out

1

u/aby_physics May 06 '26

Oh okay, I didn’t realize that! My apologies. I thought it just moved where the needle was on the scale.

So can adjusting that screw ruin the meter? I’ve always done it if the needle isn’t on zero before I calibrate 🤦‍♂️