Help fixing an enlarger (photography)


I have an enlarger for film processing which is not working. I would love it if someone electrically minded could have a look at it for me to find out if it is fixable and if it is we could fix it together?

It would be a teaching experience as well as a fix up job. I’d like to learn more about electronics so I’m not just asking you to fix something for me, but also to step me through the process.

This is my first post so I apologise if I’ve posted in the wrong section.

  • Tash

Could you add a couple of photos of the enlarger, and give its make and model. These things may help with looking up details about it on google etc.

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Good idea!

The model is an Ilford C-700 lamphouse.

Back story: Many years ago when I was a budding photographer, I bought a darkroom kit from a friend. I turned the enlarger on once, the light came on briefly then pop, and it’s never worked since. I’ve bought replacement bulbs thinking that may be the issue, but to no avail. I’m hoping it’s just a wiring thing, but not knowing anything about electronics I really have no idea. It would be handy to at least know how to troubleshoot something like this.

Here’s a link to more photos (of the entire kit) and what I believe is the instruction manual (it says 'Omega C-700):

Thanks :slight_smile:

It looks like the lamps in that do not run at line voltage (240v) and maybe DC. So there will be some kind of power supply to run the lamps. If you replaced the lamp with a new one after a “POP” event and it did not work, I would be looking around for some electrolytics that let out the green goo. If there are no popped electros present, then start looking at semiconductors.

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the manual says its designed for american voltages … a “120v, 60Hz outlet”, which means it’s made for american voltages, and unless it’s been modified for australia, it won’t work as-is. it will need a 240V to 110-120 volt converter to make australian voltages safe for it. unless for some reason the manual is for an american one, and you’ve got one that’s already been converted or something.

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Hmm, may not be the right manual after all. I coudn’t find one for Ilford online, just the Omega, but the model numbers are the same. It definitely says 240v on the power supply. I’ll take a photo of that as soon as I can find my phone…

Sorry about that. I’ll do another search and see if I can find the actual manual. But here is a picture of the back of the enlarger with the electrical information:

From that it doesn’t look like there should be much inside it. Out of interest does it say what voltage the bulb is anywhere?

If not it’s probably just a switch or a fuse that’s let out the magic smoke. Bring it in on one of our open nights and I’m sure someone would be happy to help!


I can’t see anywhere that is states the bulb voltage. I did however purchase a couple of spare bulbs, a long time ago, and I think these were based on the original bulb that came with the enlarger. Not 100% sure though. They’re PH/140, which is a 120 volt bulb.

I will do as you suggest and bring it in on an open night, along with the spare bulbs in case they are of use.

Thank you very much for your help :slight_smile:

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OK - Looking at all the photos does not look like that is the dichroic lamp housing that has a power supply and as Beau suggests is likely a just a directly wired up bulb.

You may have bought the wrong bulb if you got a 120V one. it would be unusual to have a 120V bulb in a 240V appliance (not impossible with diodes and things, just unusual)

Man am I going to feel stupid if it’s just the wrong bulb. But on the plus side that would be an easy fix.

Can you tell what type of bulb just by looking at it and poking around? I’ve contacted Ilford to see if they still have an old manual kicking around.

I’d be 98% confident that the manual you have is the right one, and the Ilford is simply a re-branded Omega (or vice versa). The enlarger is electrically identical to a bedside lamp, so there won’t be anything tricky electrically (looks like it doesn’t even have a timer, which simplifies any repair efforts) - I’d be surprised if it had a fuse, but you never know. Sounds to me like Andrew’s on the right track with the bulb, especially if you purchased a 120v version - the manual states that there is a 240v bulb available. Also note that the manual goes on about how awesome their special teardrop-shaped bulb is, but concedes that in an “emergency” a normal 211 enlarger bulb will work just fine :slight_smile:

I would hazard a guess that any enlarger lamp that is ~240v, 75W and that fits is going to be fine - there’s nothing special about the light it emits other than it being consistent across the entire negative - everything else is manually controlled when you are doing the exposure. If you were working in colour things might be different, but even then it would probably only affect your relative exposure timings on each filter.

If you spent a lot on getting the bulb then you could still use it if you had a 240v to 120v step-down transformer (although if the replacement bulb you have also “worked briefly” then it’s almost certainly blown).

Have fun! I am having olfactory flashbacks to the smell of developer solution :smiley:


If it is just a case of the wrong bulb, either of these should work fine (hopefully, I don’t know if an enlarger needs a fancy type of bulb). 70W will be a little brighter than factory, 57W will be a little dimmer. Looks like those bulbs you linked are a typical edison screw (well, very close to at least) so these should fit. Try it out and see how they go. good luck!

Enlargers often use bulbs that intentionally run hot (for colour stuff).

There MAY still be a white bulb in the boneyard in the photographic stuff box that was amongst all the photo stuff I put in the old chem room before it all got thrown out.

It was there a few weeks/months ago

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Bugger. Perhaps this post might be on the right track,

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AFAIK a 75w bulb will have a hard time running hotter than another 75w bulb unless their light output is significantly different. They will have different colour temperatures, and as you say, that probably has more to do with colour developing requirements but still, it would probably only affect the relative time for each filter.

The household bulbs will probably not be very even in their light distribution - the enlarger bulbs (probably) have a much thicker coating which gives more even light distribution to avoid a vignetting effect (to be pendantic, might also increase running temperature lol). For testing though they’ll do just fine, and if you like a vignetty sort of look they might be perfect :slight_smile:

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“Running hotter” as in the little bit of tungsten alloy running hotter :slight_smile: Not the overall heat output that warms the room :slight_smile:

Yes - the frosting is also thicker.