VTVM meter moves when my hand is next to it & not on
Posts: 19
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Joined: Aug 2024
City: Lindsborg
State, Province, Country: KS
This is strange to me. Maybe in over 50 years of working around swinging, analog meters I just never saw this, I have missed other things also along the way.
This morning I unboxed a V7 Heathkit and began investing it's innards. Looks clean has a dead carbon zink battery, not leaking yet? pulled it quickly. Noticed the 3 capacitors are original, so I plan to replace them check tubes and replaced the half weak 12au7.
Noticing the meter not setting on Zero, I decided to set it on zero. When I place my hand on the case to support it while I twist the adjustment screw the needle moves. I set the needle to zero but when I move my hand away the needle moves away from zero. Tricky little guy! So I don't put my hands close to the meter, instead l use a long screwdriver and zero the meter. With the meter set at zero I place my hand next to the meter and it jumps up swinging rather high stays up until I bring my hand back. It doesn't return to zero when it comes to rest. This is with no power on.[attachment=32248]
Bruce B
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Any metal/magnetic things IN or ON your hand?
Or it is on high sensitivity limit, and measures charge on you? Or on AC and measure somehow the signal through your capacitance?
People who do not drink, do not smoke, do not eat red meat will one day feel really stupid lying there and dying from nothing.
Posts: 19
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Joined: Aug 2024
City: Lindsborg
State, Province, Country: KS
No, I,m explaining it is turned off, not plugged in. Its not measuring anything! I don't have metal in my hand and I have moved my hand over several other meters I own without anything happening.
I have been trying to post a video but it keeps quiting at 21% so I will put this link in here and you can see what's going on.
https://photos.app.goo.gl/6tYYT8y3x3zSG1if7
Bruce B
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City: Roseville, MN
That's static electricity. Take a used fabric softener dryer sheet and wipe the dial cover then discharge your body to the nearest earth ground (or is it vice-versa?). You can now set the pointer to zero. Happens a lot in the winter-spring. Keep the dryer sheet close by.
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Joined: Aug 2024
City: Lindsborg
State, Province, Country: KS
Thanks Bob,
I was kinda figuring on that, but I have never seen anything like this guy does. It's inability to come back to rest at the same point is strange. I will see to the un-static sate of being for me and the meter, then I will try again. I'm going to recap it tomorrow and calibrate. I will then put it on the shelf as I really didn't need it, but $6, you know....
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City: Roseville, MN
Can't turn that deal down.
Posts: 19
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Joined: Aug 2024
City: Lindsborg
State, Province, Country: KS
It's okay because my wife hoards yarn, so one more piece of radio rest equipment is ok too
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City: Menlo Park
State, Province, Country: CA
Static electricity - but the other chaps beat me to it again. I've seen this before with analogue meters.
I've also seen related effects that will make liquid crystal displays (calculators and clocks etc.) act strangely, until the surface charge dissipates.
I remember using a VTVM (I think a Heathkit model) for one of the experiments in our first-year physics practicals series. Our labs were a bit archaic...
The second year lab had an AR88D in the corner - I wonder what happened to it?
I don't hold with furniture that talks.
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Ed - it's in the Cayman's enjoying the good life.
Posts: 1,401
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Haha! I hope so. It seemed rather lost and forgotten languishing in the frozen Northeast of England.
I don't hold with furniture that talks.
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