Vivitar VI w/o power supply

I was gifted a Vivitar VI with color head but no power supply or timer. The specifications indicate that the halogen bulb requires a 18V, 4.3 amp regulated power supply (from 110/120 AV input). I have seen some fancy electronics bench type supplies that will probably work. Does anyone have a suggestion for these? And, I assume that a “switching” type power supply is OK in this application? Also, the plug from the enlarger is polarized but I think that the halogen bulb is probably not. Is that true?

VinceInMT said:

Does anyone have a suggestion for these?

Click to expand...

Personally I'd consider a bench top power supply a bit on the fancy side for this application. They also tend to have lots of status indicators, 7-segment displays and whatnot to create problems in a darkroom. For a convenient and fairly affordable option, look in the direction of the variety of Chinese-made switch-mode power supplies on the market today. Most come in a simple sheet metal framing and a series of clamp connectors that you connect your own wiring to. It takes a tiny bit of electronics awareness and safety precaution to do this in a safe and effective manner. It's up to you to decide if you feel comfortable with this.

VinceInMT said:

And anre “switching” type power supplies OK in this application?

Click to expand...

Yes, in principle, they are. The main caveat is that these power supplies have a fair amount of output filter capacitance to clean up the DC output. This results in a turn-off delay; once you cut the AC power, the output caps discharge into the load (in your case, enlarger bulb) and that means it takes some time for the light to die. Given the consumption of a 75W-ish bulb, this will drain pretty quickly, and the afterglow will be very consistent, so I wouldn't worry about it.

Switching the AC side is generally preferable because it's a lot less hard on the switch used (typically integrated in your enlarger timer) than switching 4A DC.

koraks said:

Personally I'd consider a bench top power supply a bit on the fancy side for this application. They also tend to have lots of status indicators, 7-segment displays and whatnot to create problems in a darkroom. For a convenient and fairly affordable option, look in the direction of the variety of Chinese-made switch-mode power supplies on the market today. …

Click to expand...

Thanks, that’s what I’m looking at. There is one an Amazon for under $25:

Hailimayo 18V 10A Switching Power Supply Transformer AC110/220V to DC 18V 10A 180W for Industrial Automation, Electronic Equipment, Communications​

It looks like it might work. And thanks for the info on where best to switch it on and off. On my Beseler 23C I’ve been using a Time-O-Lite P49 which I assume could handle the job. I also have a GR-72 that I could use.

Yeah, something like that would work. I'd just give it a try and if the turn-off behavior is unacceptable, devise a way to switch the secondary/DC side. That'll be instantaneous. Something like a MOSFET switch would be nice, but it'll require a little DIY-ing to interface that with your timer of choice.

koraks said:

Yeah, something like that would work. I'd just give it a try and if the turn-off behavior is unacceptable, devise a way to switch the secondary/DC side. That'll be instantaneous. Something like a MOSFET switch would be nice, but it'll require a little DIY-ing to interface that with your timer of choice.

Click to expand...

I’m handier with relays than solid state. ;-) But I do know to put a diode across the relay coil to prevent a back flow when the magnetic field collapses.

But it does remind me that in the Kodak printers we had in the photo lab I worked in back in the 70s, the lamps were on all the time and they used a mechanical shutter hooked to a solenoid. I suppose the low-rent alternative would be for me to snap a piece of cardboard under the lens when the timer shuts off. After all, I’m standing right there.

VinceInMT said:

I’m handier with relays than solid state.

Click to expand...

The problem with a relays in that function is that if you switch the DC side, you'll get problems with contact welding and arcing. A relays generally just doesn't survive very long in that position. It's different on the AC side where current is lower, and it's of course AC, which matters a lot. On the DC side, a solid state switch is a better idea overall.

VinceInMT said:

I suppose the low-rent alternative would be for me to snap a piece of cardboard under the lens when the timer shuts off.

Click to expand...

Yeah, that'll work as well, but sounds a bit cumbersome to me.

I'd start by just hooking it up as any old enlarger power supply and see what happens. Odds are it'll work just fine as-is.

koraks said:

I'd start by just hooking it up as any old enlarger power supply and see what happens. Odds are it'll work just fine as-is.

Click to expand...

Yep, that’s what I’ll do. I‘ll resist planning to solve problems that I might not have.

koraks said:

The problem with a relays in that function is that if you switch the DC side, you'll get problems with contact welding and arcing. A relays generally just doesn't survive very long in that position. It's different on the AC side where current is lower, and it's of course AC, which matters a lot. On the DC side, a solid state switch is a better idea overall.

.........

Click to expand...

I have no expertise in electronics. Like a previous poster I'm more comfortable with relays etc, even rheostats(!)
Not photography, but a similar situation: I use a float switch to switch 20V DC to an irrigation pump. The first switch didn't last long for the reason cited by Koraks. Second one I fitted with a simple snubber circuit, a resistor and a capacitor in series across the contacts and it is still going strong after many years.
I'm not actually recommending it as a solution for the OP, just a possibility.

I was wondering if this enlarger has the fascinating optical light pipe. I believe it is made of optical fibers that are random and it scatters the light, like a mixing box would, but with less loss. For those that don't know, since the filters come in from the edge of the frame, if the light is not 'mixed' before it gets to the negative, only one side of the frame will have the color. Seems like a great enlarger; worth saving.

john_s said:

…Second one I fitted with a simple snubber circuit, a resistor and a capacitor in series across the contacts and it is still going strong after many years….

Click to expand...

Yes, in traditional automotive ignitions systems, this was the purpose of the “condenser” that bridged the “points,” to divert the voltage from arcing across the contacts to a “sink.”

ic-racer said:

I was wondering if this enlarger has the fascinating optical light pipe. I believe it is made of optical fibers that are random and it scatters the light, like a mixing box would, but with less loss. For those that don't know, since the filters come in from the edge of the frame, if the light is not 'mixed' before it gets to the negative, only one side of the frame will have the color. Seems like a great enlarger; worth saving.

Click to expand...

Yes, this is the enlarger that was gifted to me. I came with a 50mm Nikon lens. I have a Schneider that I use in my Beseler for my medium format that I plan to refit to the Vivitar.

A similar question arose earlier this year, and the OP of that thread found this page:

https://www.homemade-circuits.com/how-triac-phase-control-works/

I thought the circuit depicted in Figure 4 looked especially promising, as the article specifically mentions it's value in maintaining constant brightness with tungsten light sources. And what you don't want in this particular application is for bulb brightness to briefly flare up during the initial current inrush.

john_s said:

Second one I fitted with a simple snubber circuit, a resistor and a capacitor in series across the contacts and it is still going strong after many years.

Click to expand...

For an AC switch, this helps for sure and is good practice. For a DC switch, it won't do much.

4season said:

I thought the circuit depicted in Figure 4 looked especially promising

Click to expand...

Given today's technology, I'd just grab any off the shelf triac dimmer module that has active zero crossing detection. These are cheap and easy and generally take a simple logic level (e.g. 5v) PWM input or an analog pot meter control.

4season said:

And what you don't want in this particular application is for bulb brightness to briefly flare up during the initial current inrush.

Click to expand...

Running an 18V bulb from 115V AC with a triac circuit means the active part of the phase will be pretty tiny. This makes the whole thing rather sensitive to minor disturbances/deviations in the triac control, and the fireworks when the triac blows (which it ultimately does) will be rather spectacular. I'd at least then put something like an 18-24V AC transformer in front of the triac circuit. Since that will likely be more expensive than a brand new 18V DC SMPS, and likely bulkier and certainly heavier too, it's not the route I'd personally take.

Also, I'm not convinced that the inrush current of the bulb would be much of a problem, either in a DC or an AC supply scenario. It's an inherent property of incandescent bulbs and many enlargers (including color enlargers) have worked fine under these conditions for many decades.

koraks said:

For an AC switch, this helps for sure and is good practice. For a DC switch, it won't do much.

Click to expand...

Sorry this is a bit OT, and I know you know a lot more about physics and electronics than I do, but it has seemed to work. Maybe I've just been lucky with a good switch?

Hey, if it works, don't question it!

ic-racer said:

I was wondering if this enlarger has the fascinating optical light pipe. I believe it is made of optical fibers that are random and it scatters the light, like a mixing box would, but with less loss. For those that don't know, since the filters come in from the edge of the frame, if the light is not 'mixed' before it gets to the negative, only one side of the frame will have the color. Seems like a great enlarger; worth saving.

Click to expand...

I have one of these, they are actually a nice enlarger. The light pipe is not a bundle of fibers, just a solid what looks like an acrylic rod.

On a slightly different topic. Do you know happen to know how to adjust the illumination? I have the manual which is available on the internet, but it is for a slightly different model. (There seem to be a few variations of the Vivitar VI). This manual suggests to turn the "lamp receptacle" to adjust, but in my model this is only a cover which does not do anything; see page 7 of http://www.jollinger.com/photo/cam-coll/manuals/enlargers/misc/VivitarVI_Manual.pdf .

I would be grateful for any suggestions.

Joel_L said:

I have one of these, they are actually a nice enlarger. The light pipe is not a bundle of fibers, just a solid what looks like an acrylic rod.

Click to expand...

Ok, thank you for the correction. So it is maybe more like a light pipe homogenizing rod?

hsvdg said:

On a slightly different topic. Do you know happen to know how to adjust the illumination? I have the manual which is available on the internet, but it is for a slightly different model. (There seem to be a few variations of the Vivitar VI). This manual suggests to turn the "lamp receptacle" to adjust, but in my model this is only a cover which does not do anything; see page 7 of http://www.jollinger.com/photo/cam-coll/manuals/enlargers/misc/VivitarVI_Manual.pdf .

I would be grateful for any suggestions.

Click to expand...

So, rotating the lamp like the manual suggests has no effect?

No, on my (dichronic) head this is different. This "receptacle" leads to an empty hole and does not do anything. There must be a different method.

I guess I'm confused, the adjustment in the manual is to center to lamp for the condenser head. If you have the dichroic head, what are you trying to adjust? A picture would be helpful.

Ok, it seems that I do not understand something fundamental. Are you saying that the dichronic heard does not need lamp alignment. In any case, I describe the problem.

When I try to project the image to the board, then a well defined part of the image is simply not illuminated. I indicate this in the drawing attached, which shows the image as it should be (upper), vs how it is. Actually, the drawing, I just noticed, is slightly wrong. The circle goes the other way.

What this tells me is that the illumination is misaligned.

I did *something* to the enlarger, which reduced the problem, so I must have, by coincidence, adjusted in the right direction, but I am not sure what exactly it is I did.

Regarding posts #17, 20, and 22

My first—and only—darkroom printing lesson was enlarging a 35 mm B&W negative with a Vivitar VI equipped with the dichroic head and a 50 mm f/4 Fuji enlarging lens. The result was perfect. The owner, Paul Lippert from Brussels Belgium, made many excellent prints with this machine, mostly on Kodacolor papers.

The 19-volt 80-watt EKG quartz-halogen lamp as used in the Vivitar VI dichroic head has only one position—fully seated into the holder. There is no adjustment.

The diagram of post #22 is useful. Obviously, something is blocking the light path, something is missing, or one of the parts is out of position (blocking the light as described). Likely candidates are some part of the condenser assembly. That would include the frames holding the condensers in position as well as the spacers between the upper and lower condenser lenses. Be sure that everything is properly positioned as shown in the manual.

In the owner’s manual, examine the page entitled “Main Condenser Cluster” for a diagram of how these parts must be configured relative to each other.

http://www.jollinger.com/photo/cam-coll/manuals/enlargers/misc/VivitarVI_Manual.pdf

Also, be sure that there is no obstruction blocking either end of the acrylic “light pipe”. Such an object there could block a portion of the light to one side as your diagram shows.

The fact that you indicate an arc-shaped curve roughly concentric to the lens axis (and opposite to the sketch as you noted) is possible evidence of one of the condenser components being out of position. For example, if the Tension Ring for the upper condenser was out of position, its inside diameter could cast such a curved shadow.

Your problem is likely to be something simple like this. You have to carefully inspect the assembly of the parts, paying particular attention to anything with a curved edge that looks a bit out of proper position.

If you disassemble the condenser assembly to verify that it’s put together correctly, be careful. These are large glass lenses that are difficult to find replacements if scratched or broken. I like to do such work sitting on a bed so that the lens won’t fall far and will land softly if dropped.

I have the monochrome version of the Vivitar VI, and there are some adjustments possible
Not sure about the Dichroic though but in page 14 of the manual there is a section about it.
I don;t think there is much adjustment

I'm not sure what you are trying to do. There are no bulb level adjustments. The bulb snaps into place and that's it. There is a white light lever you can pull to move any filtration you have out.

The bulb is accessible through a panel on top of the head.

Do you have the condensor in place?