Aristo Cold Light Head - Help! Timer question.

[Sashazur]

We just got a new Aristo cold light head (model 57-C-V54-110V) and we're trying to figure out how to make it work right and wondering if it might be defective.

The unit is a single metal box with a switch on the side, and 2 power cords coming out - one thick 3-prong, and one thin 2-prong. The unit was shipped new but didn't come with instructions (grr!), but I found some instructions on the aristo web site. They aren't terribly clear, but I think I can puzzle out the following:

1. The thick 3-prong cord ("thermo cord") and switch ("thermo switch") are for the heater/thermostat; the thick cord should always be plugged in and the switch should be left on all day while you're using the unit.

2. The thin 2-prong cord plugs into your timer and is used to turn the light on and off.

But our unit isn't behaving as expected from the above, instead what we are seeing is:

1. If we plug in the 3-prong thermo cord and leave the 2-prong cord unplugged, we can turn the light on and off using the thermo switch. That doesn't seem to make sense since the lamp shouldn't go on unless it is getting power from the timer, right? So if the unit was working right, the lamp should never go on with the timer cord unplugged, right?

2. If we then also plug the 2-prong timer cord into the timer, it doesn't make any difference whether the timer says the lamp should be on or off, the lamp still only goes on and off when the switch is used. (We know the timer is working because we use it for other stuff).

So... If anyone is using this device or similar, please let us know if ours seems to be defective, or if we're just confused (and if so, please shed some light on the situation!).

-- Alex Benenson

P.S. I find it hard to believe that a $350 piece of darkroom equipment doesn't include instructions!

[Ken Lee]

Aristo Lighting Technologies
400 Captain Neville Drive
Waterbury, CT 06705
Tel: 203-575-3425
Fax: 203-575-3456

They have answered all my detailed questions, on several occasions.

See http://www.aristogrid.com/prod02C.htm

[Donald Qualls]

I don't know the Aristo unit, but the expected operation you describe matches my Zone VI, except that mine doesn't have a switch on the housing or anywhere else; the light is intended for external switching only. Some cold lights have an integrator output (connects a liqht level sensor for use with a compensating timer), but I wouldn't expect that to output via a mains-compatible cord, because 120 V would destroy the sensor instantly; my Zone VI has this fed out via a large DIN connector. Alternate is that the 2-prong may supply the heater (it's a low draw type, vaguely similar to an aquarium heater, just intended to keep the tube around 90-100 F to stabilize output) and the 3-prong is for the lamp (which needs a heavier cord due to startup draw); that's backward from my Zone VI, but easy to verify (i.e. if you plug both in and operate the lamp for 15 minutes, then unplug the 3-prong and check in half an hour, is the lamp housing still warm?).

I agree, however, that it's a little strange that *any* substantial piece of new equipment doesn't include some kind of operating instructions -- especially electrical/electronic equipment with significant safety hazards if operated improperly, in addition to the likelihood of damage to the unit. I'd start by contacting the dealer who sold you the unit, followed by the distributor for Aristo or the manufacturer directly.

[Sashazur]

Donald, thank you for the tip regarding the possibility that the cords may be reversed. I'm trying what you recommend now - just have the 2-prong cord plugged in and the switch on to see if the unit gets warm. I'll let you know what happens. If you're right, then Aristo's online instructions need to be fixed!

[Sashazur]

Donald, you were right. Thanks very much. I'll send an email to Aristo letting them know that their online instructions need to be fixed (and that they need to include instructions WITH the unit too!).

[Donald Qualls]

:D

Glad it was something simple...

[resummerfield]

I would also open it up and trace the wiring. I have a T-12, and the heavy three-wire cord is the heater cord which runs through an on/off switch and a thermostat to small heaters, and the thinner two-wire cord is the timer cord which runs directly to the transformer. The operation of my T-12 matches the instructions you found on the Aristo website, and I think is pretty standard for cold lights.

[Sashazur]

Eric, I looked inside, see the pics below. I assume the little gold things are the heaters? The wiring is not easy to trace, everything seems to be interconnected. If you can see anything informative in the pictures, let me know.

http://sashazur.lunarpages.com/pix/coldhead.JPG

http://sashazur.lunarpages.com/pix/coldhead2.JPG

[Sashazur]

OK, I've done further testing and now I am convinced the unit is defective. I took the cover off and plugged each cord in turn into AC power and then both cords (I was VERY careful!). Here's what I found:

When the 2 prong (thin) cord alone is plugged in, the heaters get hot, whether the switch is on or off (I'm assuming the heaters are the small gold/brass colored things in the pics above).

When the 3 prong (thick) cord alone is plugged in, the switch turns the lamp on and off.

If both cords are plugged in, the above behavior doesn't change, which means the heaters are on and the switch controls the lamp.

[resummerfield]

I've been looking at your pictures, and looking at my T-12. Except for the number of heaters (gold things), they are almost identical.

The thick, 3-prong cord on my T-12 connects through the switch and a thermostat (that's the small device that the green ground wire connects to) to the heaters. When I plug in my thick 3-prong cord, the switch controls the heaters. It has to be this way, so that you could leave the unit plugged in, and switch the heaters off when not in use.

The thin, 2-prong cord on my T-12 connects directly to the transformer/lamp grid. There is no switch because this thin cord connects to a timer, which is then the switch.

I've looked carefully at your pictures, but I can't be certain. The wiring is just too hard to follow in the pics. But if your unit operates as you describe, then it is wired wrong. Don't even think about re-wiring it, because it would void any warranty. Call the vendor and raise hell, and demand a new unit and reimbursement of shipping!

[Chuck Pere]

My 1212 also works opposite. The 3 prong cord and switch control the heater. The 2 prong cord works the lamp directly not through the switch. Looks like yours is wired wrong. I would call Aristo and explain the problem. They worked well for me over the phone. Maybe they can also talk to the vendor. And if the same vendor sends another one maybe they can check it out prior to shipping.

[Sashazur]

Well, I finally got ahold of Louise Kessler at Aristo and I learned that the unit is operating correctly and their instructions were wrong.

The 2 prong cord IS for the heater, and the 3 prong cord IS for the lamp, and the switch DOES control the lamp (but it should always be left in the 'on' position obviously, since the lamp should really be controlled by a timer).

This is all different from the instructions on their website, and Louise told me that they'll be fixing those instructions soon (they are at http://www.aristogrid.com/Tech02A.htm and by the time you read them they may already be fixed).

Louise also confirmed that my unit should have included instructions and should have had the cords labeled correctly, and she apologized for all of these problems.

So, Aristo leaves me unimpressed:
- Their website instructions were wrong.
- There are no instructions specific for the unit, they're "generic" for a group of products.
- They forgot to include instructions with the unit and forgot to label the connections.
- The unit has a switch on it that serves no useful purpose.
- I sent them a fax, and an email, and a voicemail (at business hours), and I didn't hear back from them (even to get an automatic response) until 2 days later.

But at least I can use the #$*&# thing now!

[resummerfield]

That sounds just a little strange to me. So Aristo has changed the wiring from that used on my T-12 and others, to REMOVE the switch from the heaters, and put a switch into a circuit that does not need one (and then tell you to leave the switch on)? Maybe Aristo has a reason for this? Still, it sounds a little strange. Still, I would NOT leave the heaters plugged in when you are not in the darkroom!

[Sal Santamaura]

Well, I finally got ahold of Louise Kessler at Aristo...So, Aristo leaves me unimpressed...I also spoke to Louise yesterday in a quest for information about a 1212 and had the exact opposite, i.e. a positive, impression:

Aristo was purchased by Voltarc and inherited the Web Site. Improvements are needed and will be made. Voltarc is completely shut down for inventory and vacation at this time. Reaching Louise was a bonus for both of us.
Manufacturers of photo equipment, particularly darkroom-related items, are leaving the business in droves. That Aristo was sold rather than closed is a good thing. I'm thrilled they're still there.

Granted it would have been better if you didn't have the problems, but I'm going to support Voltarc in this transition/improvement phase.

[Bob Pellerin]

I own an Aristo45 Hi-intensity cold light, bought new in 1988. The instructions recieved with it covered more than one model. The generic installation for the 4x5, 5x7, 8x10 section matched the physical unit - the thinner wire with the 2 prong plug connects to a timer to control the light, and the heavier cord with the 3 prong plug controls the heaters and is wired through the toggle switch.

However, some of the cold lights, even back then, are different. Same instruction sheet - Beseler 23 section - says that on that unit the 2 prong plug is the heater and the 3 prong is the timer and you need to turn the switch to "on".

At the very least one of the cords should have been tagged "thermo" (mine is) so there would be no mistake.

The enlarger I bought it for is long retired, but the cold light makes a terrific light box and copy light and lives on.

[Sashazur]

Yes, Aristo overall hasn't impressed me for the reasons I outlined, but I was very satisfied with my conversation with Louise, she seemed very honest and helpful. But I agree it seems strange that the wiring of their units has apparently changed for no good reason, and therefore I am still wondering (just a teeny little bit) if I got a cock-and-bull story. Anyway, it does seem like the unit is usable - I don't care if it's miswired as long as the rating of the wires is sufficient.

-- Alex

P.S. I do realize that Aristo is one of a quickly-shrinking set of suppliers of these types of products. I hope my experience was NOT typical of their quality and customer service since the company changed hands, otherwise there are even more reasons to worry about Aristo's future!

[Chuck Pere]

The 23c unit had the transformer in a separate box. That box had a switch. The heater cord went directly to the lamp with no switch. Guess you don't really have a problem but I wonder about Aristo's explanation. Too bad you can't get a second unit to try or get the vendor to check it's operation for you.

[John Powers]

Alex,

Reading through this thread it is not clear to me if you have had earlier experience with cold light heads. If not there is at least one more surprise ahead that early warning may at least prepare you to address. I have a 1212 and found that there is no consistency between one 16 sec exposure and the next. I thought perhaps this was where your "timer question" was going.

When I bought the enlarger with cold light head, the former owner Michael Mutmansky told me RH Designs has a cold light head timer version called the Stop Clock Vario. It has a light sensor that you position right in the lighting area. It senses how much light is coming out on each exposure so that each 16 second exposure has the same amount/intensity of light as the next. Pretty important if you want your print to match your step test. I have been using it for about a year now and am very pleased with results. Search here and on APUG.org for RH Designs and other very positive reviews.
http://www.rhdesigns.co.uk/darkroom/html/stopclock_vario.html#note

Hope this saves you the pain of an ugly surprise.

John Powers

[Donald Qualls]

John, this must vary from one head to another. The light output of the fluorescent tube is very dependent on temperature; too cool, and it's dim, too hot, it gets dim again. It's brightest at around 115 F, and most of these heads have an internal heater that can keep the tube within a few degrees of that temperature; if that heater isn't working correctly, you can see considerable variation between one exposure and another as the head heats up (with more on time) or cools (with more off time).

For whatever it's worth, I can't see the difference between multiple exposure of the same value with my Zone VI head; I start each enlarging session with a minimum fifteen minutes of tube-on (while I fill trays and set up the rest of my temporary darkroom), and leave the heater on for the entire session, to ensure consistent head temperature. And I'm using a plain old Graylab 300 timer, almost identical to one I used in high school in the mid-70s.