Too long printing times with De Vere 504

[Philippe Grunchec]

My 504 (the brown/beige type) has also been modified by a former owner : it uses two ELH 120V 300W bulbs, which is very convenient with slow papers, lith printing, large sizes, etc.
Yesterday I got a 5108 (same colours!) that uses the same bulbs.

 

[Jesper]

Maybe I misunderstand your point Tom, or maybe you misunderstand mine.

Running two 110/120V lamps in series is what you do when you want to use 110/120V lamps in a 220/240V environment and in that case (running 2x2 lamps as you do in a 5108) you will get 1200W (mostly heat but a lot of light).
If you use the same 2x2 setup in 110/120V you will have half the voltage but the resistance will be the same. At best you will then get 300W (if the lamps will behave equal to the voltage at any level, but they will most likely be dimmer).
In a 110/120V environment you run the lamps 4x1 instead to get 1200W (if you use that setup in 220/240V you will experince a very, very brief moment with 4800W)

 

[Tom Kershaw]

I was referring to a 4x1 set-up in a 120V environment.

Tom

 

[Martin Aislabie]

I recently picked up a De Vere 504 with Dichromat 504 head (free standing model with baseboard that can be dropped).
It is equipped with a De Vere 500 W twin Stab. I thought it was standardly equipped with a Transtab?

Anyway, I seem not to get enough light out of it (definitely not 500W). I get printing times of up to 15 min for a 20 x 25 cm print...

So I suspect the problem could be the Twin Stab but I'm not very good at electrical stuff.

Does anybody have any thoughts or suggestions?

Thanks

Getting back to the OP

My 504 Mk4 uses a single 24V 250W Bulb

I understand that the Mk5 uses 2 off 24V 250W Bulbs

Check your Enlarger Bulbs – what Wattage and what voltage they are actually getting supplied at

Martin

 

[Jim Taylor]

Hi!
I have the benchtop 504, with the single lamp (250W) version of the dichromat head and the appropriate transtab...

Been in the darkroom for a couple of hours today for the first time since Christmas and was faced with a similar problem to the OP - Exposure times shot up from their normal 10-20 sec. to 2-3 minutes.

After much scratching of head; I discovered that a piece of the polystyrene inside the mixing box had fallen out of position, and was laying accross the diffuser plate on the bottom of the mixing box. I just unscrewed the top of the mixing box and repositioned the polystyrene inside. Light output and exposure times are now back to normal.

Perhaps if you've only recently got this enlarger (i.e. moved it from somewhere else) something might have slipped inside the mixing box? In mine, the styrene is only held in place by friction - no glue!

It's less than a 5 minute job to take the top off the mixing box and have a look? Something to rule out, if nothing else!

Cheers.

 

[JonathanLocke]

Light mixing box: checked.

But we're advancing: I checked the voltage at the lamp holders and get 11V at both, while the lamps are 24 V/250W and they appear to be connected serially (if I take one out, the other one does not light). As already posted, I'm really no genius in electricity but my line of thinking is now to change the serial connection into a parallel one to get 24 V (or 22) for both lamps. If that would do the trick, hip hip huray...

Let me know if I'm right or if I'm just proving my utter electricity stupidity...

And then there's still something nagging in the back of my head: why on earth?
Does the setup come standard like this? I cannot imagine (the transfo reads 500W switch tab) but then why would anyone change the output of the head so that it gives less light??

always thankful for your thoughts...

 

[ic-racer]

I'm kind of following from a distance here because I don't know that particular head, but it seems like you are on the right track, good work!

 

[Mick Fagan]

When I first got mine I didn't know it was set for 110 volts, I went into the transformer didn't know what was what as I'm not a sparky, took it to a friend who is a whiz with things like that and he switched something either internally or externally and it then worked on 230 volts, which is what we have here.

I assume a transfo is a transformer?

Does sound as though you are on the right track.

Basically these machines are designed to run on different power supplies so they can run anywhere in the world, you just require the correct switching.

Mick.

 

[Jim Taylor]

Glad to see the mixing box wasn't the problem. At least that's one thing ticked off!

Sounds like you're making progress on the power front!

I've been mulling it over this afternoon and have attacked my mk-IV 250W (single lamp) head with a multimeter. If it helps, I was getting 29.5v~ across the lamp connector.

Now, moving on...

Out of curiosity, I then proceeded to lift the lid on my Tran-Stab…

Pardon me for being so forward, but… Does yours look anything like mine?

If you look at where the pen is pointing in my pic, you’ll see that 29.5 is stamped onto the block – surely it’s no coincidence that this is the voltage I’m getting across the pins in the lamp-head.

So… something else for you to try; do all the wires in the row of terminal blocks correspond to 240v – or do any suggest that this has been used in a 110v environment? Also… (this is assuming the layout of your unit is similar) is there any indication of what voltage you should expect at the lamp-head?

By opening up your transformer and just having a look you can potentially work out: -

1. Whether the unit has been used in a non-240v environment, and not converted back for use in the UK;
2. What voltages you should expect to get at the lamp-head;
3. Whether there have been any amendments or changes to the wiring in the lamp-head. (If these were wired in series as standard by De Vere, then I would expect the voltage on the lamp-head to be around 50v (24x2))

(You don’t need to change anything at this stage, just get back to us with a report of what you find!)

Just as an aside… my Tran-Stab has the voltage rating stamped on the back; sounds simple, but have you checked that it's definitely the 240V model? (I have no idea whether there are any other differences between the 250W and 500W models, other than power output)

One other thing... when opening the Tran-Stab take it slowly - most of the screws that poke through the chassis are holding the transformers in place. If you're not sure, I'll happily send you pics of the screws I took out to get inside! Obviously, there might be differences between the 250W and 500W models.

And now, a disclaimer: I’m not a sparky, the extent of my knowledge is through an amateur interest and an A-level in electronics, gained many years ago. Needless to say that anything you do is entirely without warranty and at your own risk!

 

[JonathanLocke]

Ok, news from the powerfront:

we changed the wiring of the lamps into a parallel connection but then my Switch Stab (nobody mentions this model? Everyone's talking about tran-stab?) started producing an irregular bzzzz- noise which caused the lamps to flicker so I assume my Switch Stab was not up to the task I was asking from it. Although it states clearly on the front: Switch Stab 500W

So; jimbop, thanks for the extra info, i'll have a look tomorrow if I can detect something similar in my transformator and will get back to you.

Only possible explanation I can think of indeed is someone could have changed the switch stab for a 110V environment?
Although it clearly states at a back panel: 240 V - 5 ampère - 50-60 Hz.

But I still believe I can fix it one day!

More news tomorrow.
Tx to all contributors!

 

[Jim Taylor]

The rating on the back panel you mention is the same as on mine.

When you connected the lamps in parallel, were they any brighter than they had been when they were connected in series?

What voltage were you getting across the lamps?

My Tran-Stab is working fine, and it always issues a gentle buzz - it's not uncommon with old/high power transformers; especially when they're supplying a heavy load. Probably not a good idea to run it for too long like that though .

I don't know if the attached photo is any use. It's a shot of the lamp from my enlarger taken using a 28mm lens at ISO 400, 1/4000 sec @ f/29. I metered on the brightest part of the filament. If you could take a photo using the same camera settings and then compare them - it might give you some idea of whether your brightness is anywhere near mine... I'm not sure how useful this would be, but it might give us a chance to see just how dim things really are, if we have some comparative photos. The lamp in this shot was REALLY bright - it hurt to look at it, and I was VERY quick to take the photo!

Don't know if it's any help, but just a thought!

Jim.

STOP PRESS: Having said all of this, I've just found a picture of the Switch-Stab, and internally, it looks very different from my Tran-Stab.

Have a look and see for yourself, but it may be time to concede defeat and give John a call at odyssey-sales.com - they were very good when I got some bits from them!

 

[JonathanLocke]

no no no, no defeat.

we took the transformer apart and found that there are actually two parts delivering the power.

took one out (the fuse) and still got 24 V at the lamp so we suspect the part with the fuse works.

did the same other way round and got ... 4 V. So probably one of these two parts is broken. Will take it to an electrician now...

hasta

 

[Jim Taylor]

Glad that you're sticking with it; I must admit, it's not my usual self to admit defeat, so must have been having a pessimistic moment last night when I wrote my last post!

Keep us informed of what you discover - this problem has aroused my curiosity!

The measurements quoted in your last post, 24V and 4V... are they DC or AC voltages (or a mixture!)? The reason I ask is this: -

If the transformer you have is a more modern version of the Tran-Stab (which seems likely, from what little I can find online) and if (again, as in my setup) this unit also provides power to other electronics (e.g a microprocessor controlled exposure timer) then the ~4V output may be correct (CMOS devices often run on ~5V DC).

Also... the top is still off my Tran-Stab, so I went in with the multimeter.... if you're measuring AC voltages in DC mode, some multimeters register a voltage. Now; when measuring a known 130V AC, my multimeter reads 4V DC. Be careful not to frazzle yourself!

Just a thought!

Cheers,

Jim.

 

[ic-racer]

Maybe I missed something but a most important thing is that your wire from the power outlet goes to the correct tab on the transformer primary, as shown by the picture posted above by jimbop

 

[JonathanLocke]

just a quick update to gently round up the subject: honestly, still haven't found what the problem is... Even electricians refuse to touch the inner parts of the switch stab. I do have some guesses what could be wrong BUT... I put the lamps from serial to parallel and I put only one lamp in it instead of the two and... bingo, I get a lot more light out of it. Enough to be around 8-15 secs for a 20 x25 cm print from a 6x6 neg.

For the moment, this will do. Later on, when I have some time I'll look into it to find what the problem really is. For the moment, I can work on.

In any case, thanks everyone for your help and comments.

j

 

[ic-racer]

I bet if you can open up the box and take some digital pictues and post them for jimbop to see this can be solved. I reread these posts and it seems like jimbop's #1 suggestion above is very likely:

1. Whether the unit has been used in a non-240v environment, and not converted back for use in the UK;

 

[MR CORONET]

Too long exposure times with De Vere 5108

I have a DeVere 5108 and a typical exposure time with that one is 10-30s (16x20" print). 15 minutes is definetely wrong.[/QUOTE]


Hi,
Jjust setting up my second-hand 10 x 8 enlarger and the bulbs i have are domestic 240 v, 50 w , four bulbs. My exposure time for 10 x8 prints are around 75 sec for a 21 step stouffer (21 steps: i can see 10 grade on my old Braclay paper/PD5 developer) or a 35 mm neg or 54 x 4 neg with a variety of lens (similar times) . I have checki only ave 240 v powersuplly, no switches to alter on it. Timmer does not work.
My question is what bulbs can i use in this enlargers to get faster exposure times please?

what bulbs do you have jesper?

Gerry

 

[MR CORONET]

De Vere 5108 long exposure times and help with focusing pulleys/wheels needed!

Hi,
Just a quick update, still no reply form my seller. Contacted Osdessy, very helpful, now have bough correct bulbs, 300 W , 110 Volts x 4 of each. Hoping it will work and connect to my analyzerPro. Will write when i have the bulbs.
in mena while any suggtsions on howto fous when wires to the two wheels at th eback are broken,

Anyone with a 5108 who know how the pulley wire work could they contact me , please ?
Gerry

 

[Jim Taylor]

Hi Gerry - I've only got the 504 benchtop model, but I can scan and send you the diagram for how this should be set-up, if you think it will help - drop me a PM with some details and I'll e-mail you the scan.

 

[MR CORONET]

Have sent a Pm to you hope it gets there, bring back the tin cans and string !!Gerry

 

[clayne]

Wasn't there a common issue with De Vere's and the continuity of the light sockets themselves? Oxide build up over time causing a lack of current flow and/or arcing which kills bulbs and possibly other electrical efficiency issues.

 

[Tom Kershaw]

I've been printing some fairly dense 4x5" TMY-2 negatives with the DeVere 5108 and have been using exposures in the 30 to 50 second range @ f/11 (Rodenstock Rodagon 150mm)

Edit: This seems to be my 2000th post here on APUG.

Tom