Hello to anyone who is reading this.

I have an SPI Metal Halide Lamp that only works part-time. And most of
the time it won't light up right, it just flickers away without much
output.

I don't know much about this kind of lamp. My theory is that if the
lamp will light properly, if even for brief moments, then the bulb
itself is probably okay.

Becasue of the trouble it has getting the bulb to light properly, I
have a theory that the ballast is the likely culprit. Am I close to
the truth, or close to being a dufus? Maybe I'm way off.

The ballast consists of a fairly hefty transformer from "Advance" rated
for 400w and 300v. The capacitor is a metal can rated for 24uf @400VAC
with an internal resistanced of 1.0 Megohm.

How doe one troubleshoot this combination? I have another theory that
would like to believe that it is the capacitor at fault. Perhaps it is
wishful thinking. How does one test whether the cap is working
properly?

I have a good Beckman multimeter and desoldering/soldering tools, a
good assortment of hand tools, large and small, and some skills. Just
not with ballasts and lighting. Any help, procedure, advice is much
appreciated.

Thanks,
Phil Simpson.

"UnclePhil" wrote in message
oups.com...
Hello to anyone who is reading this.

I have an SPI Metal Halide Lamp that only works part-time. And most of
the time it won't light up right, it just flickers away without much
output.

I don't know much about this kind of lamp. My theory is that if the
lamp will light properly, if even for brief moments, then the bulb
itself is probably okay.

Becasue of the trouble it has getting the bulb to light properly, I
have a theory that the ballast is the likely culprit. Am I close to
the truth, or close to being a dufus? Maybe I'm way off.

The ballast consists of a fairly hefty transformer from "Advance" rated
for 400w and 300v. The capacitor is a metal can rated for 24uf @400VAC
with an internal resistanced of 1.0 Megohm.

How doe one troubleshoot this combination? I have another theory that
would like to believe that it is the capacitor at fault. Perhaps it is
wishful thinking. How does one test whether the cap is working
properly?

I have a good Beckman multimeter and desoldering/soldering tools, a
good assortment of hand tools, large and small, and some skills. Just
not with ballasts and lighting. Any help, procedure, advice is much
appreciated.

Thanks,
Phil Simpson.


When I was doing street lights a lot we found that 2 caps to a transformer
was pretty typical. Cap boosts the start voltage so that the lamp can
strike.
you could have a bad cap, bad lamp or a bad transformer. I would start with
the cap if the transformer is producing the correct voltage.
There used to be testers that could be screwed into the lamp holder to tell
ya what was wrong.
Been a long time ago for me. Maybe things have changed.

John Grabowski wrote:

I don't spend a lot of time testing things. I just replace the ballast,
capacitor, photocell if installed, and the bulb and know that the customer
will have a reliable light fixture for a few years. It would not make me
look good to replace one component only to have another fail several months
later.

I'll second that. Also, these days a new fixture is sometimes cheap
enough that it's usually cost effective
to just replace it with a new one and be done with it. If the OP
insists, I'm sure that he can Google for "Troubleshooting HID light
fixtures" and get more info than most people would care to know.