Omega Chromegatrol

Hello all:
I do not use or have any Omega Chromega heads so I am not sure how this timer / power supply should function if not connected to the Chromega head.
With unit turned ON:
1) In FOCUS position there is a hum/buzz (not unlike a Gra-Lab 300 buzzer on a low setting), if EXPOSE switch is used the hum/buzz continues
2) In PRINT position there there is no hum/buzz, however when EXPOSE switch is used there is a hum/buzz but it times correctly and the hum/buzz stops at the end of the selected time.

I have taken it to an electronics repair shop with the schematic I found on line but they advised that without the Chromega head they could not test any further.

Model number is 412-040.

Is this normal if not connected to the Chromega head?

Thanks in advance.

Todd

So to clarify - does the head workas it should, just with a buzz as it's exposing?

I do not have a head to test the timer/power supply with so I can’t answer your question. Sorry

As far as I know, the Chromegatrol is dedicated to Chromega heads. It is not a stand-alone timer that can be used with other heads.

The buzz you are hearing seems to correspond to when the enlarger head lamp should be powered. That circuit is not complete, since you don't have a head plugged in, so the buzz may be some consequence of that, or maybe your unit just buzzes a little when the bulb circuit is on.

The actions you describe suggest that the unit is working properly, but you won't know for certain till you hook it up to the correct head.

Best,

Doremus

Todd Barlow said:

I do not have a head to test the timer/power supply with so I can’t answer your question.

Click to expand...

This is a bit like the old quip about the sound of one hand clapping. If you don't have the head to go with this power supply and timer, does it matter whether it works...?

Supposedly, you'd like to know in order to sell or donate. Consider to do so 'as is' with the description you gave of what it does. Then leave it up to the buyer/recipient to figure out where to go next.

That, or borrow/buy/steal a fitting head to test with.

It is pretty easy to test, it is not an 'electronically regulated' power supply; just a ferroresonant transformer with a timer. Do you get 22.5V AC at pins #8 and #9 or across the secondary of the transformer when the "Expose" or "Focus" buttons are depressed?

Ferroresonant transformer (or just about any other large transformer) will hum when operating.

Usually these units fail in the timing circuit, not the transformer, so I'd be sure to test the timing circuit before getting the head.

With regards to the comment above from ic-racer about the timing circuit failing.
I have/had this same Chromegatrol with head.
I didn’t use it a lot but it used to work fine. Recently I dug it out of the cabinet where it had been sitting for several years and tested it before an upcoming move. No matter the time set it would just flash on then off. I found if I left it plugged in warming up it would respond better but the timer was still off considerably.
I can’t remember if I packed it and brought it with me on my recent move; I’m pretty sure I kept the head at least.