Spotlight lamp won’t turn on

[Eli Vatsaas]

We have a Comet follow spot with a lamp that won’t turn on. The lamp was getting dim so I replaced the lamp. After replacing the lamp, it wouldn’t turn on. I know it’s not the lamp since it worked in another spot. How do I get it to work. The fan turns on fine, just not the lamp.

 

[JD]

Two things come to mind. The socket of course, and the transformer. Most run the lamp at 82 volts with a step-down transformer. These transformers have an internal thermal fuse. If the lamp had a shorted filament it may have overheated the transformer. Unfortunately, if this is the case, the transformer would have to be replaced.

 

[Les]

I agree with @JD - aside from a bad toggle switch, those are about the only two things that can go wrong with the Comet's lamp circuit. If you have a multimeter, you might be able to meter the voltage at the socket. Dim lamps could have been a failing transformer, but it also could have just been the fact that those MR lamps tend to get foggy reflectors and/or lots of carbon buildup on the inside of the lamp capsule as they reach the end of their life.

How did the pins look on the old lamp? That will tell you a lot about the condition of the socket. I had to replace a few of these after about 15 years of service. Kind of a pain, to be honest. Altman didn't think to make those easily field replaceable as it requires drilling/replacing a few rivets and butt-splicing a new socket and lamp carriage. Only about $14 in parts but easily an hour of labor.

 

[Addictedtogaff]

I agree with @JD - aside from a bad toggle switch, those are about the only two things that can go wrong with the Comet's lamp circuit. If you have a multimeter, you might be able to meter the voltage at the socket. Dim lamps could have been a failing transformer, but it also could have just been the fact that those MR lamps tend to get foggy reflectors and/or lots of carbon buildup on the inside of the lamp capsule as they reach the end of their life.

How did the pins look on the old lamp? That will tell you a lot about the condition of the socket. I had to replace a few of these after about 15 years of service. Kind of a pain, to be honest. Altman didn't think to make those easily field replaceable as it requires drilling/replacing a few rivets and butt-splicing a new socket and lamp carriage. Only about $14 in parts but easily an hour of labor.

Hi there! I now have the same problem as this post. I cannot find any material on how to replace the socket. How do you replace the socket on the comet?

 

[Les]

Hi there! I now have the same problem as this post. I cannot find any material on how to replace the socket. How do you replace the socket on the comet?

Hi to you as well! Check your PM's.

 

[ship]

Not a end user repair at this point. With your above PM's or factory authorized repair for it, where I work included.

 

[Addictedtogaff]

Not an end user repair at this point. With your above PM's or factory authorized repair for it, where I work included.

Nope! I was actually able to repair it in time for the show. I overnighted a new socket, got some cheap harbor freight tools, and spent half an afternoon fixing it. It works perfectly!