Nikon Scope Issue (Labophot 2)

[wtrv]

Hello,

I just purchased a Nikon Labophot 2 but unfortunately I encountered some immediate issues.
It appears in otherwise excellent condition but when plugged into a ground-fault circuit interrupt outlet (https://en.wikipedia.org/wiki/Residual-current_device) it trips it every time when increasing illumination past ~10%.

I'm just wondering if this is normally encountered in older scopes due to interference/inductive loading or if this represents a serious hazard. If anyone knows about this happening in older scopes help would be greatly appreciated before I try a non-GFCI outlet. I believe it's a halogen bulb if that makes a difference.

Thanks!

[MichaelG.]

I would say this respresents a risk of a serious hazard

Bear in mind that your hands and eyes could be in contact with the instrument.

The protected outlet is apparently doing its job ... Be thankful.

If you have the skills and tools to do so; check everything.
... If not; then find someone qualified.

MichaelG.

[apochronaut]

Bear in mind though, that gfci's are very sensitive and work by detecting a differential to ground of only 6 ma or so. They don't work very well with certain electronic circuits too . I have had one or two of my microscopes trip a gfci intermittently. Since the problem begins after 10% , then it is likely a small ghost leak of increasing current, maybe in more than one spot. I would take the panel off and check to make sure all the wires are routed freely and not touching, remove dust and check for anything untoward, then try it again. Insulation isn't perfect and a few cumulative ghost leaks could be the problem.
A dirty rheostat might do it too, if that's what it has.
If the problem persists after a cleanup and rearrangement , maybe have an electrician check and see how much leakage there is.

For years I used a stove that would light an led occasionally when it wasn't turned on.

[75RR]

This might help: Labophot2-Pol Instructions

Make sure it has the specified Halogen Bulb installed.

http://earth2geologists.net/Microscopes ... ctions.pdf

[Hobbyst46]

My primary suspect would be the contacts of the power cable: the plug connection, the connection to the board within the microscope, and if the cable is replaceable, I would replace it. 1St Law of Electrical and Electronics Common Failures.

[wtrv]

Bear in mind though, that gfci's are very sensitive and work by detecting a differential to ground of only 6 ma or so. They don't work very well with certain electronic circuits too . I have had one or two of my microscopes trip a gfci intermittently. Since the problem begins after 10% , then it is likely a small ghost leak of increasing current, maybe in more than one spot. I would take the panel off and check to make sure all the wires are routed freely and not touching, remove dust and check for anything untoward, then try it again. Insulation isn't perfect and a few cumulative ghost leaks could be the problem.
A dirty rheostat might do it too, if that's what it has.
If the problem persists after a cleanup and rearrangement , maybe have an electrician check and see how much leakage there is.

For years I used a stove that would light an led occasionally when it wasn't turned on.

Update: It's the rheostat
Turns out the rheostat chip was damaged during shipping. This was probably causing leakage after the 10% mark which was where the contacts touch on it (distant end on picture). Thankfully I just purchased it and the seller is willing to take returns. It's a real shame though since this Labophot was in otherwise great condition. I'd replace it myself but it looks like the chip is in there pretty well.