Replacing enlarger power supply

[polyglot]

My current plan is to get a new linear regulated power supply such as this guy:
http://www.ebay.com/itm/Samlex-RPS1...ly-used-great-working-condition-/370724961156

And to use a 80-100W bulb that uses the same mount (there are many) and is matched to the voltage of whatever power supply I find. In some cases, I'm even seeing power supplies where I can adjust the voltage so maybe if I find one of those cheaply enough I won't even have to change the bulb, and could switch to a 12V later without getting a new supply.

That's not a good power supply to get. If it's linear then it's hugely inefficient, and you don't want 13.8V because there aren't really 13.8V bulbs on the market. 13.8V is designed to run automotive accessories (CB radios, etc) because that's the approx full-charge voltage from a lead-acid battery.

Since you're planning on replacing the bulb, using the common 12V or 24V halogen bulbs (e.g. MR16) and power supplies (eBay 400306116935; note that's 220V though) that are used for kitchen lighting is the easiest option. You can buy all of those bits at your local hardware store pretty easily and cheaply, though high power bulbs seem more easily found online (eBay 75W 400331920368 or 100W 290622077567). You'll maybe need to buy an MR16 socket; I don't know what's in the enlarger.

You can also get cheap 12/24V industrial switching supplies that will run halogen bulbs, e.g. eBay 160768220046. You do need to do some mains wiring for those though, which is best avoided by buying an all-in-one switching halogen supply ("electronic transformer" is how they're often branded) designed for lighting that has a cord and plug on it already.

 

[treddy]

I was under the impression that switching power supplies were not good for enlargers. But they are ok, if designed for other halogen lights?

Tim

 

[polyglot]

I was under the impression that switching power supplies were not good for enlargers. But they are ok, if designed for other halogen lights?

Enlargers heads are basically just light bulbs so switching supplies are quite capable of running them. Light bulbs are mostly resistive, which makes them a well-behaved load.

The only possible issue you might have is that if you use a digital enlarger timer with triac output, that's somewhat incompatible for some switching supplies - it might not switch on reliably. Make sure your enlarger timer has a mechanical output relay.

 

[ic-racer]

Yes, if that is a capacitor that would explain it. In that case maybe the capacitor shorted then went open circuit and the transformer is still good. I'd check the windings and, if Ok, source a new capacitor.

 

[Noble]

Hello,

I recently got a free Vivitar VI enlarger, but the power supply is broke. (Turned it on, got some sparks, then smoke, then nothing...) and I'm trying to replace it. The output is rated at 18.44VAC and 4.5A (ust over 80W).

One idea I had was a laptop power supply.

Check your local market for enlargers. I'll put it to you this way. I needed a particular size negative carrier for my enlarger. All the nice modern mint condition ones were going for about $50. I just bought a newer enlarger which had multiple carriers covering the sizes of interest for a little over $30. It's perverse but I'm noticing just going out and buying entire enlargers is cheaper than buying even relatively simple parts. Your local market may vary, but I would encourage you to search Craigslist. Even if you have to drive a bit it's got to be better than risking your money and life tinkering with suspect electronics.

 

[chris a fraser]

hello Treddy (and all)

This my first post, and wondering what you did.I just bought the same enlarger with the same problem. were you able to repair the power supply?

chris

 

[Ralph Javins]

Good morning, Treddy, and Chris up in B. C. too;

I am impressed with the number of knowledgeable people who recognize that the Vivitar V1 Enlarger power supply is a regulated AC supply using a ferro-resonant regulating transformer. That transformer has three (3) windings where the winding with the black wires is the 120 VAC primary or input winding, the winding with the white wires is the regulated output lower voltage secondary winding, and the third or tertiary winding with the red and yellow wires is the regulating winding that works with the capacitor. The tertiary winding with the capacitor is the "resonant" part.

Others have already commented on the necessity for getting a replacement capacitor of the same value and AC voltage rating, although the AC voltage rating can be higher, but the value of the capacitor in ufd or Micro-Farads must be the same. The exact capacitor value is important. An AC voltage rated "motor starting" capacitor of the same value will work.

There are some other very simple ways that we can get around the death of the proprietary transformer if that has happened. One very simple way is to get a Sola type CV or CVS constant voltage transformer (there are some other brands also) with about a 90 Watt or 100 Watt rating, and replace the dead transformer and its capacitor in the power supply with just a simple low voltage transformer of about an 18 VAC at 5 Amperes rating. It may be called a "filament transformer." It will go between the black primary wires and the white secondary wires. When you plug the cable on the power supply into the external constant voltage transformer, you will move the voltage regulating function from the power supply out to the external constant voltage transformer, but the voltage lowering function stays in the power supply this way.

Yes, there may be a slight changing of the color temperature of the light with the possibly slightly different voltage, but it can be compensated in the filter pack if truly needed. Try some test prints in color and see how it looks to see if this is necessary. With black and white it will not be truly necessary.

Oddly enough, the V1 Enlarger is one of the very few things that Ponder and Best, or "Vivitar," actually did make in California.

 

[tkamiya]

Just for the record....

I did try adopting what I had, which is a switching power supply for laptop rated at 15 volts, 5 amps. I actually got an unexpected behavior. With this supply connected to the lamp, there was no output - most of the time. Few times, after few seconds delay, it would come on but other times, no voltage what-so-ever. If I had the lamp disconnected, the voltage would appear and I could connect the lamp and it will continue to work. When it worked, there were definitely some delay.

From this, I suspect, some of this type of power supplies are more than just a switching regulator that there is some "intelligence" built in. Also, I suspect the start-up current of typical lamps that are significantly higher than "ON" current may also be a factor.

Obviously, this is not suitable for this kind of use.

I'm flying blind here but since OP said "spark" "smoke" and "capacitor showed no obvious sign of problems", I suspect the issue is either the transformer wingdings or a power switch. Oil caps usually fail catastrophically. Bulging out or oil leaking all over the place.

 

[mr rusty]

To Chris Fraser

The V1 is a really good enlarger IMO. (OK I'm biased because its what I have), but whatever else, it has glassless negative carriers and absolutely cold light, so no neg popping. This plus a full range of adjustments and a very sturdy post makes for a good unit.

Persevere in getting the light fixed/modified.

 

[chris a fraser]

Hello Mr. Rusty

I have used many different enlargers over the years and from the looks of this enlarger it looks great. I bought it from our local city museum (along with a Omega Prolab D6) and both enlargers are in great shape. Both came with a variety of lenses, neg carriers, development tanks, archival washer..... I couldn't pass it up.

I am looking into having the power supply fixed, then I will decide on which to keep. Might be forced to decide on the Vivitar simply based on hieght.

chris

 

[Jackson Warner]

I just got a Vivitar VI enlarger and it had set it up and was cleaning the lenses when I smelled smoke and the power supply was smoking and dripping fluid which I think was electrolytes from the capacitors. If anyone has one they'd be willing to sell that would be great

Thanks