Super Chromega Dichroic II D - Bulb Not Working

[Technorama]

I was doing some printing with one of my Super Chromega Dichroic II D equipped enlargers yesterday when the main bulb suddenly quit. Burnt out bulb was my assumption. Changed to a new bulb, still no light. Swapped in the power supply and timer from my other Super Chromega Dichroic I D enlarger, which works just fine, and still no light from the first enlarger. On the first one, the problem appears to be in the head itself, and not with the power supply, timer etc. The fan motor will run, but no light. Is there a component inside the head, such as a fuse or something, that also needs to be checked or replaced ? Appreciate any insight and guidance.

[ic-racer]

Maybe time for a new lamp socket. I’m replacing those sockets all the time in my track lights, lawn lights and enlargers.

[Mark Sampson]

That sounds about right. I worked with numerous Super-Chromega enlargers for many years and the lamp socket was the most common failure point.

[HMG]

I don't remember seeing one in the Chromega Dichroic (though not II) head. There's no mention of the fuse in the manual for that head. But, IIRC correctly, the light and fan are powered separately from the power supply, so the fan could work and the light not work with a defective power supply.

[Tin Can]

Could be a tiny Thermistor

Common on many circuits for overheat protection

They have set high temperature and don’t reset

They are often near invisible

$2 part

[Technorama]

Thanks all for the ideas. Will do more checking later today. I assume that if I test across the two spade terminals for the bulb socket leads on the distribution block inside the head, I should get 24v.

[Doremus Scudder]

My most common repair to my Chromega heads is also the lamp socket. I have a six-pack in a darkroom drawer and change them out fairly regularly. That's likely your problem too.

FWIW, I've wired mine in with wire nuts on the existing leads for easy change-out.

Best,

Doremus

[Technorama]

Good news !!! Well, sort of. Found the source of the problem. A broken wire within the main cord from the head that prevented the 24v from ever getting to the bulb. Making repairs and installing new parts -- including bulb socket -- to get the unit working again, and hopefully for years to come.

Again, thanks to all for insights, information and guidance.