Omega F 8x10 enlarger

[Carl J]

Mine came with an EPOI timer (Ehrenreich Photo Optical Ind.) but it's not accurate and don't know if or how to re-calibrate and without the power relay (originals are rare and expensive on KHB) the timer should be 1000w capable, but it sounds like 750w works as well. I've looked at the Lektra timers, which supposedly are built like tanks and can be re-calibrated but haven't been able to convince myself to actually buy one. Also have the motorized power lift for focusing which is convenient but not essential.

[ic-racer]

I have one w/Dichroic head and am trying to figure out (have questions) how to wire a power-relay to use with a modern timer. What kind of timer are you using with yours?

See: https://www.photrio.com/forum/thread.../#post-2101596

Mine came without a baseboard so I'm improvising for now. I like that drop-table setup in ic-racer's post (can't tell from the photo if that has the standard base or if attached to the drop-table).

Nice to see they are still well-regarded even if not that common. Yes, KHB is a good resource.

This might help:
https://www.ato.com/how-does-lighting-contactor-work

[Erik Larsen]

I have one w/Dichroic head and am trying to figure out (have questions) how to wire a power-relay to use with a modern timer. What kind of timer are you using with yours?

See: https://www.photrio.com/forum/thread.../#post-2101596

Mine came without a baseboard so I'm improvising for now. I like that drop-table setup in ic-racer's post (can't tell from the photo if that has the standard base or if attached to the drop-table).

Nice to see they are still well-regarded even if not that common. Yes, KHB is a good resource.

Here’s the McMaster Carr part numbers 7384k21 and 7384k45 for relay and box enclosure that I use for my enlarger. You can use any timer with the relay installed. Forgive the crude wiring diagram, I’m no electrician but it was a simple project. And remember I’m not responsible if you burn your house down!

[ic-racer]

[Dave Ogle]

here a couple of photos of my "F". its been modified but works for me. have a Rodenstock APO Graphigon 240mm. also have a Rodenstock 300mm. you can see turn buckle set up I used to mount and level enlarger. no base

[Carl J]

Many thanks to both Erik and ic-racer. I did pick up the power relay and enclosure corresponding to the McMaster-Carr part numbers. It's a Deltrol Controls (#20239 83) single-pole double-throw relay with 5 numbered terminals for wiring. From your sketch looks like not all are used. Attaching a photo to maybe help with orienting me to your drawing. Ha! sorry, but still a bit greek to me (obviously I'm not much for following even simple schematics).

Thanks

[neil poulsen]

Years and years ago I had my chance at new one for $700 with the color head. (Sans negative carrier.) But I already had a Zone VI Type II VC 8x10 attachment, so I didn't see the need. Nor would I have ever printed 8x10 color film. But definitely, someone got a good deal on that enlarger.

[Erik Larsen]

For Carl J, Here’s a pic of the relay wired up. It is different than the pic you posted. Note that you will need a male plug end for the “wall outlet” cord and the “to timer” cord and a female plug on the “enlarger power supply” cord as shown in my rough drawing above. I hope this helps. Here’s a link to the one I have. https://www.mcmaster.com/7384K21/

[ic-racer]

Many thanks to both Erik and ic-racer. I did pick up the power relay and enclosure corresponding to the McMaster-Carr part numbers. It's a Deltrol Controls (#20239 83) single-pole double-throw relay with 5 numbered terminals for wiring. From your sketch looks like not all are used. Attaching a photo to maybe help with orienting me to your drawing. Ha! sorry, but still a bit greek to me (obviously I'm not much for following even simple schematics).

Thanks

Yes it is different than the one in post #19, it can be wired normally open or normally close. You'd want normally open, so one terminal won't have a wire on it. Do you have the PDF for it?

You might consider grounding the box. If any of the 3 black wires were to come loose, the box could become a live wire. If the box is grounded, and a black wire comes loose and touches the box, it will trip the breaker first.

In fact the wiring in post #19 is a little scary as the box is not grounded and I don't see that any of the ring connectors are crimped or soldered to the wires.

[Erik Larsen]

Yes it is different than the one in post #19, it can be wired normally open or normally close. You'd want normally open, so one terminal won't have a wire on it. Do you have the PDF for it?

You might consider grounding the box. If any of the 3 black wires were to come loose, the box could become a live wire. If the box is grounded, and a black wire comes loose and touches the box, it will trip the breaker first.


In fact the wiring in post #19 is a little scary as the box is not grounded and I don't see that any of the ring connectors are crimped or soldered to the wires.
Carl j, follow ic racers advice about attaching a ground wire to the box somehow as remember I’m not an electrician! The wires are firmly crimped in the eyelets but if they somehow become disconnected Zap! I think I’ll add that ground wire right now…