How to tell if a MH bulb is bad, or the charging circuit?

[CMOS]

Hey All,

I have a canopy with dual PC sockets and a single MH socket. My MH circuit stopped working a few days ago so I'm trying to see how to best troubleshoot.

Is there a way visually, or electrically with a VOM, to test the bulb itself? If not, short of just replacing the bulb, any way to troubleshoot this?

Thanks for any help.


CMOS

[FoMoCo Master Tech]

You should be able to check the bulb for an open ( continuity) with a VOM or DVOM by ohm testing the power and ground contacts of the bulb.

[CMOS]

VOM shows a complete OPEN between the power poles of the bulb. I'll order another bulb.

Thanks for the help.


CMOS

[CMOS]

Follow up: It appears that the Reisitive measurement method does not work on a MH bulb. I went to my LFS and borrowed a brand new bulb and measured the contact resistance right there on the spot. A full open circuit measurement just like my "old" bulb.

It makes sense: MH lighting is created when the Halide gas is excited within the small bulb chamber in the center of the main bulb, therefore measuring a MH bulb in the same manner as a tungsten filament bulb, well, just won't work.

No sure what I did to fix it, but after taking my light system apart and giving everything a good blast with some compressed air, the MH circuit is now functioning.

CMOS

[FoMoCo Master Tech]

In retrospect, that makes sense. I didn't realize MH's use an arc, rather than a filament. My mistake. Glad you got it figured out though.