De Vere 5108

[BJC0000]

I've managed to get my De Vere 5108, which has been in storage about 15 years, reassembled'

It has a Dichromat head, a De Vere control box and a De Vere old timer (with turnbuckle knobs)

When I first turned it on and selected 'focus' the lamps lit up.

Since then no lights work.

Power is getting through - the fans work and the facia lamp lights, but not the main lamps.

I've tried every combination of power/focus I can with no joy. Fuses appear ok.

I've even replaced one of the lamps but still nothing.

Any suggestions - it's driving me mad!

 

[Ian Grant]

It;'s probably a switch setting on the control box. Justgone to my darkroom, cotroller Mains -On, Focus - Off, and the timer should be on, and working.

Ian

 

[Carnie Bob]

I've managed to get my De Vere 5108, which has been in storage about 15 years, reassembled'

It has a Dichromat head, a De Vere control box and a De Vere old timer (with turnbuckle knobs)

When I first turned it on and selected 'focus' the lamps lit up.

Since then no lights work.

Power is getting through - the fans work and the facia lamp lights, but not the main lamps.

I've tried every combination of power/focus I can with no joy. Fuses appear ok.

I've even replaced one of the lamps but still nothing.

Any suggestions - it's driving me mad!

I own two Deveres , vintage 80's and recently I have had issues with the timers on both , though I know I am not answering the OP question properly, I had Ian Leake make me a new timer that has cords to match the back of the transformer and the enlarger now works fine-pricey but effective. My thinking that transformers have less likelihood of going bad and it seems I was right. This happened on both 11 x 14 and 5 x 7 enlargers, I will probably sell the 5 x 7 as I am bringing my condenser Omega back into production. KHB in Ontario Canada can and will sell you new parts for all Deveres.
The OP should have a competent technician (electrician) look at the head, transformer and in my case replace the timer. Not sure what year your unit
was built , but mine units are now 40 years old and over time the wiring in the head may have gotten brittle with age and may be giving problems. In the 5 x 7 we had just recently heard a very loud pop sound go off in the head, when investigating the bulbs were fine but inside we can see all kinds of melted plastic laying about, kind of like a short going off in a confined space.
I also would add I never found any of the Devere timers accurate under 10 seconds so I always used them between 10 and 20 seconds to minimize any drift.
Good luck with this , these machines are relics but in my opinion some of the finest samples of simple engineering in our end of the buisness.

 

[Ian Grant]

Unplug from the mains, The pairs of 300w 120v lamps run in series, check them, if one of a pair is blown the other won't work. Chances are the pins have oxidised slightly in 15 years of storage. I had to clean the lamp holders on mine.

It's possible to use 250W 120v, instead of 300w, lamps, these are cheaper and have a far longer working life.

Ian

 

[koraks]

In addition to what @Ian Grant says (and if that doesn't work), consider the switching relays in the timer. If you have a voltage stabilizer unit with yours, it may have issues due to leaky tantalum caps. I fixed one a few weeks ago: https://tinker.koraks.nl/photography/solid-as-a-rock-fixing-an-old-ac-stabilizer/

 

[BJC0000]

Thanks for the replies - I've had it for tonight but I'll give some more time to it tomorrow. What I don't understand is how the lamps lit the first time but won't play subsequently - I switched them off - they didn't go out of their own accord - no bangs, crackles or pops. It seems a bit of a stretch to think more than one lamp has failed at the same time.

Ian: I'll try cleaning contacts and replacing lamps and see if that helps; I do have a number of new lamps I could try.

Koraks: I read your article linked above but it's beyond my ability to try anything vaguely similar - simple household electrics, yes but electronics, no.

I have the 507 version of this enlarger working well in my darkroom. The timer looks identical. Could I swap them and see if that's the problem? Of course it has a control box rated at 500watts if I put just 2 lower-wattage lamps in could I see if they lit without doing any damage? Just trying to isolate the problem.

Thanks again

 

[koraks]

Koraks: I read your article linked above but it's beyond my ability to try anything vaguely similar - simple household electrics, yes but electronics, no.

Yeah; that was mostly to illustrate that some pretty specific things can go wrong and those would require more specialist attention. However, start with the more obvious things.

If you have a multimeter/DMM, you could verify if there's voltage on the bulb sockets and/or the output of the timer. You'll have to set your DMM to HV AC. If you're not familiar with this, watch some YouTube videos and pay heed to the safety warnings you'll probably come across. It's perfectly safe to poke around with a meter as long as you're reasonably careful and aware of what you're doing.

What I don't understand is how the lamps lit the first time but won't play subsequently - I switched them off - they didn't go out of their own accord - no bangs, crackles or pops. It seems a bit of a stretch to think more than one lamp has failed at the same time.

Hence my remark about relays. They're the electromechanical elements that do the switching and they can malfunction. It's rare, but this is old equipment and especially if it has spent considerable time sitting around under less than optimal conditions, contacts can corrode or the mechanism can stiffen up. What you could try is give the timer a couple of firm blows with your fist; just bang on it nice and hard a couple of times - preferably when it's on and the bulbs are supposed to be switched on.

The timer looks identical. Could I swap them and see if that's the problem?

In principle, yes, but...

Of course it has a control box rated at 500watts if I put just 2 lower-wattage lamps in could I see if they lit without doing any damage?

Is the output voltage the same? I suppose so, but you need to verify. I've not worked on DeVere's a lot; we mostly get Durst around here so I'm more familiar with them. IDK what different flavors of the DeVere timers are kicking around.

 

[Lachlan Young]

The timer looks identical.

The De Vere timers are identical. Unplug it from the control box and plug it in to the 5108 control box. Sometimes the relay inside the timer can fail. Or, if you have a spare timer plug for the control box (RS has them) you can wire it up as a shorting plug (see the De Vere manuals online) to operate the control box without a timer. Opening up failed De Vere Universal timers (the later smaller ones) is a bit of a fiddle - and much of the time people replace them with other timers.

Of course it has a control box rated at 500watts if I put just 2 lower-wattage lamps in could I see if they lit without doing any damage?

If your 507 is running the 500w dichroic, then it's using 24v ELC bulbs. The 5108 head is running 120v ELH (or ENH as Ian Grant suggests) bulbs. I think you can see the problem here.

Sockets, switches, relays, capacitors are all potential points of failure. The good news is that the most complex bit of the circuit (apart from the timer) is the 5108 stabiliser that Koraks has linked to above.

 

[BJC0000]

Thanks for that Lachlan - very helpful.
The 507 is indeed running 24v lamps so couldn't use that Transtab in any way but I will try the timer.
Tried that - no light, so went back to basics; took all the lamps out and replaced them with new ones and 2 of the 4 came on!

The pairs of 300w 120v lamps run in series, check them, if one of a pair is blown the other won't work. Chances are the pins have oxidised slightly in 15 years of storage. I had to clean the lamp holders on mine.

So it looks like I might have spent 2 days plus trying to find a more involved answer than Ian's about cleaning contacts. (Both timers light the lamps so that's ok).
Best get the cleaners out tomorrow.

Thanks again to everyone
Barry