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  1. #21

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    IC-Racer,

    It's a ferro resonant transformer. Behind the steel plate on upper half of the box, there is a large oil filled capacitor. That and the extra winding on the transformer act as a regulating mechanism. (I have the same unit right here)

    OP:

    I'm afraid to give you any instructions because you appear to be not familiar with this type of circuits. There are only few things that can fail. One of the windings can blow or short, capacitor can leak, overheat, or in rare cases, short, or the switch can go. Testing require a live circuit and I definitely won't recommend you'd try it. You said "spark" "smoke", etc. Since I don't see any liquid leaks or burn marks, I'm GUESSING power switch may be the issue. If you have a multi-meter, you can check the switch. Beyond that will be a risk worth not taking.

    Are you going to print color or B&W? If B&W, voltage regulation isn't important. Any transformer that is capable of producing the proper voltage and current will do. If you were closer to me (I'm in Central Florida) I'd take you to one of the surplus shops around here and hook you up with a proper switching power supply.

    Despite what has been said, most of current Laptop power supply does not use battery as a regulator. If that were the case, you can't operate the laptop without a power supply. (and I can). I also did a load test with what I have. It is certainly regulated. I have a 15 volts 5 amp supply for Toshiba, so I tried it with my Vivitar VI. There WAS a problem. It appears it has some kind of a protection circuit. It won't reliably produce output when lamp was connected. It works if I let it come up to voltage first, then connect. If I keep it connected and power up, it won't. So in enlarger application, it won't work. At least the type I have won't.
    Last edited by tkamiya; 02-16-2013 at 10:16 PM. Click to view previous post history.
    Develop, stop, fix.... wait.... where's my film?

  2. #22
    mr rusty's Avatar
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    If you're building a replacement bulb mount, include some fine sliding adjustments to get it all aligned. Don't put a higher-powered bulb in the enlarger unless you upgrade its cooling
    If you do go down the replacement bulb route, this isn't necessary. The V1 uses a standard size dichroic projector bulb, albeit an unsual rating. Suggestion is use a same size but different rated bulb to use standard lighting transformer. The bulbs front face is the positioning mechanism. You might have to change the mount to suit a different rated bulb. The V1 has passive cooling. I doubt 80W to 100W will cause a problem.

  3. #23

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    Thanks for all the help everyone -- this has been extremely helpful!

    I've thrown in the towel on repairing the power supply. I just don't know enough about what I'm doing, as is clear. While the sparks and smoke were fun and all with the case on, not so much with the case off

    My current plan is to get a new linear regulated power supply such as this guy:
    http://www.ebay.com/itm/Samlex-RPS12...-/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.

    It seems that most voltage regulated supplies are switched nowadays, so it has been trickier than I expected to find a linear regulated supply. I have a few options I'm working on, but they all are of the hobby type. While I'm fine with that, any other suggestions on a good source for a new linear regulated supply?

  4. #24

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    Quote Originally Posted by treddy View Post
    Looks pretty nasty inside. I'm guessing the orange/yellow coating all over the inside (some sort of fluid leaked out all over the place?).


    Attachment 64244

    Is the big thing in the middle the capacitor in question, or is that the transformer?

    I found a laptop power supply listed at best buy that is 19V, 100W for something like $30. Might be an easier way to go, I'm thinking? If the output is controlled enough to not fry a computer, I imagine it would be ok for enlarging too?

    Tim
    Actually, it looks very simple for an enlarger power supply. That is a ferro-resonant transformer (the big thing with brown coil windings), which works with the capacitor (the other thing) to regulate the voltage. These capacitors frequently fail, and my guess is that was what happened. You can probably replace it easily, but the value (microfarads and voltage) is critical, and you need to replace it with something with the same ratings. As for the computer power supply, it looks like that would work fine. Your enlarger does not seem to have any strange circuitry, just a regulated power supply and a lamp. Before you buy the supply though, check to be sure the power wiring goes righ to the lamp and that there are no additional electronics in the enlarger. If there are, you may need the regulated ac supply, not the dc you get out of the computer supply. You may be able to find a local electronics hobbyist of ham radio operator who can help you.

  5. #25

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    Quote Originally Posted by nworth View Post
    Before you buy the supply though, check to be sure the power wiring goes righ to the lamp and that there are no additional electronics in the enlarger.
    Yup, the power supply is directly connected to the light with a couple twist on wire connectors.

  6. #26
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    Quote Originally Posted by treddy View Post
    My current plan is to get a new linear regulated power supply such as this guy:
    http://www.ebay.com/itm/Samlex-RPS12...-/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.

  7. #27

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    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

  8. #28
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    Quote Originally Posted by treddy View Post
    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.

  9. #29
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    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.

  10. #30

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    Quote Originally Posted by treddy View Post
    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.

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