De Vere Universal Timer

[Tristan H]

Hi !
For my first post, I'm searching how to fix my De Vere universal timer. It has issues on the second selector, and works only for the tenth and the one-tenth seconds. Ex : When I turn the selector to 2, 3, 4 or 7 sec and push the exposure button, nothing happened (but I could hear a click), and for 5 or 6 sec, the timer count 1sec.
I strip down the timer and put some spray in it... but of course, no effect. Here some pics, if there are some electronic engineers here
Any idea how to fix it ?

 

[Anon Ymous]

Welcome Tristan!

Unfortunatelly, not enough can be seen from the photograph. A closeup would be needed to figure out more, the integrated circuits' markings aren't clear. That said, it's very likely that one of the rotary selectors (seconds) has faulty contacts. Additionally, one or more dry joints at the selector's pins could also cause such a problem. Have a very close look there with a magnifying glass. If any joint seems cracked or lifted, then it could be the problem. It seems to be in good condition and being a fairly simple device, there isn't much that can go wrong with it.

 

[ic-racer]

Sometimes you can take the lid off the relay and clean the contacts with DeOxit.

 

[paul_c5x4]

I strip down the timer and put some spray in it... but of course, no effect.

What spray did you use ?

It could be as simple as a dirty contact in the switch or slightly more complex in that one of the chips is faulty.

 

[Tristan H]

A spray for contact, the same kind as DeOxit.
The circuit seems in good condition and the selector turn like the others.
I'll take more pictures later.

 

[Anon Ymous]

BTW, you can unscrew the standoffs and take a photo of the back of the pcb as well. While you are at it, inspect for dry solder joints - cracks, especially at the pins of the middle rotary switch. That is the problematic part, isn't it? If you only use the tens of seconds and tenths of seconds (for example 20,3, or 10,7 seconds) the timer works ok, is that correct?

 

[Sirius Glass]

Welcome to APUG

 

[Tristan H]

Hi everybody,
Thanks for the infos and answers.
I can't see any joints, surely because I wasn't be able to find a way to disassemble the selectors.
Here more pics of the timer.
Wouldn't it be the potentiometer faulty ?

 

[ic-racer]

Does the relay operate? The diode at the base of the relay is across the activation coil. Check for voltage relative to ground there when it is supposed to be ON.

 

[Anon Ymous]

Tristan, the "joints" I was talking about are the solder joints which connect the pins of the rotary switches to the printed circuit board (pcb). If they're cracked, then they might have intermittent connections, and/or high resistance, making the timer erratic. Of course, the switch itself might have unusually high resistance because it is worn. In order to check it, you would need to have a multimeter and measure the resistance of the contacts (in the low Ohm range). This assumes that you'll find out which pairs of pins make a contact internally.

The bad thing is that these switches seem to be hermetically sealed. I doubt that you can do anything about them, apart from replacing them.

 

[Tristan H]

Hey guys !
So I didn't fix the timer. So I tried another one a friend gave me (De Vere electronic timer). But it didnt work either... At last, I put my Ilford 500 Mutligrade head. Everything works fine now... At least for the timer !
Is there somebody who have a ilford head on a De Vere 504 ?
I have few questions.
1- My negative carrier (original one) is not blocked when I lower the head, I can move it and I guess i should not.
2- Is a 504 user could join me a pic of the light boxes inside the head (I know the Durst's ones are longer) ? My 35mm's box is alright but my 6x6 seems not to be an original one (a Omega maybe ?) since the lights are not placed good (the bulbs are not in front of the box's holes).
3- (the million dollar question) Where can I find a 4x5' box for De Vere ?
And to finish, happy new year !
Here some pics

 

[MartinP]

It is several decades since I used a De Vere 504 at work (I now have a 203, at home) but I recall that the neg-mask fits in to a carrier, with built-in masking arms, by means of a sprung clip and a couple of catches. The alloy plates I see in your picture remind me of the fast-swappable neg-mask, rather than the carrier as a whole -- you may be missing a few parts. As the weight of the head is on top of the carrier it should be simple to make up something flat and of the correct thickness to keep the neg-mask in the right place - try a model-making shop for thin plywood etc.

When I was using the 504 it was with a De Vere colour head, not the Multigrade one like you have, so I am unable to comment on the light-box. If you want to find original spares for De Vere enlargers, the current UK licence-holder and refurbisher seems to be Odyssey Sales.

The De Vere machines I have used have been very well designed and a pleasure to use. Good luck!

 

[nworth]

You say that the timer works for the tenths of a second range (I presume it works properly for that, including actuating the relay). I would then suspect the seconds decade counter (one of the ICs). You need to probe the timer circuits appropriately with a logic analyzer to see where the failure is. The switches are also a definite possibility. They are notoriously unreliable, but they usually fail intermittently. The circuits and switching arrangements in timers vary a bit from design to design. If you can get a circuit diagram (try the DeVere website), it will make life easier.

 

[Tristan H]

Hi, thanks for the answers.
I definitely forget to fix the DeVere timer. I dont have a logic analyzer and like I said I find another way to make my enlarger work properly. But maybe it could help others members.