test mercury vapor bulbs

Is there a way to test mercury vapor bulbs (with the large mogul base)? I need to isolate a problem with a large outside yard light and isolate the issue between the bulb and the photosensor.
Thanks for any tips.
John Keith snipped-for-privacy@juno.com
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No real way you can test the bulb alone, other than to swap with a known good one, or in another working fixture But if the photo sensor is the plug and twist type, you can check voltage there easily enough.
Why aren't you asking about the ballast ?
AMUN
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wrote:

Because I'm just learning about these lights. I assumed that the bulbs were the most likely to fail and they are easily replaceable. What do I need to learn about the ballast? Is it replaceable or does one just replace the fixture to fix a ballast?
John Keith snipped-for-privacy@juno.com
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John Keith wrote:

--
WARNING:

Do NOT under any circumstances take advice from an idiot named AMUN.
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You can pretty much think of them the same as a fluorescent strip, if that helps. Testing of the parts is pretty similar for all gas discharge type lighting.
Easiest way to test a bulb is in another working fixture. Or try a known good spare.
You can not simply go by a $2.00 ohmmeter continuity test, as you can with a regular incandescent bulb.
But depending on the light sometimes the ballast is worth more than a replacement fixture.
AMUN
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Amun wrote:

Your advice isn't worth $.02
--
WARNING:

Do NOT under any circumstances take advice from an idiot named AMUN.
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