Rewiring a Focomat 1c : LUSENET : Leica Photography : One Thread

Has anyone rewired a Focomat 1c? I've been trying to do that this afternoon, without success. Could anyone shed some light on what I'm doing wrong? Back in the UK I was pretty handy with electrical work, but since I moved to the US everything's different, and I'm definitely in the novice category.

Guessing at the vintage of this enlarger, I think it's one of the ealier models. It has a brown wooden baseboard, and I read that the later models had white baseboards.

The enlarger looks as though it was supplied for the US market, as the plug attached to the baseboard has 2 flat pins. However the plug which inserts into the top of the enlarger column looks European, with 2 round pins. That second plug needs to be replaced, along with all wiring in the column and underneath the baseboard.

Having removed the 2 round pin socket held inside the column, I realized that it was a factory sealed unit. European plugs and sockets aren't readily available over here, so I decided to bypass the column altogether. I didn't see any kind of voltage adaptor in the column or under the baseboard, so I assumed that I could run the cord directly to the mains.

I replaced the 2 round pin plug with a US 2 flat pin plug (white wire to wide pin, black wire to narrow pin), with the intention of using an extension cord to connect it to my enlarger timer.

My first test worked fine - the lamp came on and stayed on when plugged directly into a GCFI recepticle (grounded socket for folks outside North America). But then I adjusted the height of the lamp socket, and only in certain positions would the lamp come on.

Making sure the lamp socket was at a functioning height within the lamp house, I reassembled the enlarger & plugged it into the timer. Nothing happened. I tested the timer and it was fine. So I plugged the lamp house into the mains and promptly blew the circuit. I took it back to the GCFI recepticle and blew that circuit too. The wire from the lamp house to the new 2 pin plug felt excessively warm to the touch.

I don't know where to start diagnosing the problem. Any ideas? Pretty please?

Thanks in advance for any suggestions.

-- Stuart Dorman (, March 17, 2002


Stuart: From an old FCC-licensed and Air Force trained radar technician turned mental health counselor:

Here's the main clue:

"But then I adjusted the height of the lamp socket, and only in certain positions would the lamp come on."

This observation suggests that the wiring in the vicinity of the lamp housing is faulty. There is an intermittant connection in this wiring, very possibly (but not definately) at the point where it connects to the lamp socket. In other words, there is a wiring connection that is mechanically unstable.

There is a second fault, very possibly related to the first: The hot wire (the one that isn't the neutral) is shorting to the enlarger housing, I think. Does the enlarger have a three-wire plug with grounding prong? If not, then the two wires are just simply shorting together.

Take it all apart and make sure that all wires are well insulated from each other and everything else. Use electrical tape and spaghetti (the name for insulated sleeving) over all bare wire areas.

There is some concern that you may have damaged the timer by connecting a shorted device to it. I wouldn't do that again until you have all the bugs out of the enlarger. Feel free to re-post or email.

-- Bob Fleischman (, March 17, 2002.


Ditto what Bob has to say. Cords in the US are built to certain standards. You are correct that the white wire goes to the wide blade, but in the event you are using a cord without color coding, the conductor with the ribs or stripes on it go to the wide (neutral) blade. I believe I have the same enlarger as you. I would check where the cord goes into the sliding piece for bulb adjustment, and possibly where the cord connects to the bulb socket base. I would be more likely to suspect where the cord first enters the sliding part for the bulb placement. E-mail if I can help.

-- Mark A. Johnson (, March 17, 2002.

Bob & Mark - thank you both for your advice. I have actually decided not to do any further modifications to the 1c, as it was on loan from a friend. Being a loaner, I didn't want to do anything else which coulf cause damage to the enlarger.

The other reason I discontinued my rewiring job was that a V35 arrived on my doorstep yesterday. I should soon be cranking out the prints with my latest acquisition.

Thanks again. This is such a great forum, with so many people willing to offer advice and help. I'm hoping that soon enough I'll dispensing as much useful help as I continue to receive.

-- Stuart Dorman (, March 23, 2002.

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