UV Light Box Died

[Joe Lipka]

Last night, it was time to start printing for the alternate process print exchange. Poured the chemicals, humidified the paper I coated Sunday night, heated the developer, even had the vacuum frame pulling 25" of Hg.

I turned on the UV light box, the fan went on, the bulbs didn't light up. The UV unit was purchased from the Palladio Company about 1991. (Boy, things just don't last the way they used to.)

The things I said made the picture of my wife's grandfather blush (and he was a sailor!).

Any suggestions on how to determine which (or all) of the ballasts need to be replaced? I have included a photograph of the wiring and a close up of a ballast.

 

[Steve Smith]

If none of the bulbs/tubes(?) light then it is not likely to be a ballast at fault and it is highly unlikely that all four would fail at the same time. It looks like you have four identical circuits wired in parallel so if they don't work, it will be something more fundemental such as no power getting to the ballasts.

If you have a multi-meter you could check for voltage at the ballast terminals.

EDIT: I would check for voltage at the junction of the four sets of black and white cables which (from your pictures) look like the power connections. They disappear off of the bottom of the picture but I imagine that all four blacks are joined and all four whites are joined and this pair is the voltage in.



Steve.

 

[juan]

Also, are you sure there's power at your AC outlet? Seems basic but I've looked for circuit problems that turned out to be a blown breaker. Also, is the light unit fused? Is the fuse good? I agree with Steve that it sounds like something other than a bad ballast.
juan

 

[Joe Lipka]

The fan works, the bulbs don't light up, so there is power getting into the unit. I have a circuit tester, but no multi-meter. If memory serves me well, I do believe Steve's guess on the wiring connections are correct.

 

[Bob F.]

The fan works, the bulbs don't light up, so there is power getting into the unit. I have a circuit tester, but no multi-meter. If memory serves me well, I do believe Steve's guess on the wiring connections are correct.

There may be separate fuses for the fan and lights inside the box. Also check the connections between the switch and the lights - one may have come loose.

Good luck, Bob.

 

[Michael Mutmansky]

Joe,

It is probably a wiring fault or a fuse. Go to the junction of the black wires and check the junction. Pull the wire nut and redo if it doesn't look solid. Do the same for the white wire junction. (WITH THE UNIT UNPLUGGED, PLEASE)

Before you do that, look for an in-line fuse in the wiring that connects to the ballasts, probably on the black line. The often look like a piece of plastic about the thickness of a pen or marker and about 2 inches long. It should be possibe to unscrew the connector and check the fuse. There may be one on both black and white wires.

Look for a fuse that is accessible from a cap on the outside of the unit as well. There may be two of them, one for the whole unit, and one for just the ballasts.

Without a multimeter, it's a bit hard to go through the circuiting without a bit of trial and error, but that may be how you will have to do it.

Steve is correct, the lamps will be wired in parallel.


Do you really use 25" of hg? I never use more than about 5". I figure there's no need to squeeze harder than is necessary to produce good contact. Less likely to damage the negative.


---Michael

 

[Steve Smith]

If you don't have a meter to check with, you could connect a lamp holder with a low wattage bulb fitted to the black and white wires to see if you have power at that point.

Obviously, I don't know your level of confidence/competance when dealing with electrics so if you are not sure about this, the answer is to not do it and get it checked professionally.


Steve.

 

[Dave Wooten]

are the bulbs wired in a series?

 

[Joe Lipka]

Joe,


Do you really use 25" of hg? I never use more than about 5". I figure there's no need to squeeze harder than is necessary to produce good contact. Less likely to damage the negative.


---Michael

Yes, I do pull it to 25" of Hg. There is anecdotal evidence to suggest higher vacuum increases separation of the high values. PM me if you would like to discuss this obscure observation in more detail.

 

[sanking]

Yes, I do pull it to 25" of Hg. There is anecdotal evidence to suggest higher vacuum increases separation of the high values. PM me if you would like to discuss this obscure observation in more detail.

I also suspect the problem is an blown in-line filter. That would certainly be the best solution.

If you have any real evidence that shows an increase of separation of the high values with high vacuum pressure I would be very interested in seeing it. My experience is that more than 5-10 inches of mercury is plenty, and that more pressure can be detrimental in some cases. However, I am open to modify my thinking on this if there is evidence to the contrary.

Sandy

 

[Jim Noel]

Try the simplest solutio first.
SOmetimes for an unknown reason my grounding doesn't cause the bulbs to ignite. I just reach in and run the back of my hand over the tubes and they light.
It is worth a try.
Jim

 

[Michael Mutmansky]

If you have any real evidence that shows an increase of separation of the high values with high vacuum pressure I would be very interested in seeing it. My experience is that more than 5-10 inches of mercury is plenty, and that more pressure can be detrimental in some cases. However, I am open to modify my thinking on this if there is evidence to the contrary.

Sandy

That is my feeling as well. I've seen a vacuum frame squeeze liquid out of the fibers of an otherwise dry piece of paper and ruin a negative, so I am wary of using any more pressure than is necessary to obtain good contact.

I don't adopt a procedure unless it has proven performance benefits, so I'll try a comparison, but I am somewhat skeptical that it will improve the highlight detail with my printing conditions.


---Michael

 

[sanking]

I don't adopt a procedure unless it has proven performance benefits, so I'll try a comparison, but I am somewhat skeptical that it will improve the highlight detail with my printing conditions.


---Michael

I would have to add that even if highlight detail is improved by increased pressure it is something of a moot point with me since using over 20 inches of mercury is really not an option with inkjet negatives on the substrates I use, Pictorico and Clearprint. That much pressure would simply pull the ink off the substrate during exposure and fix it to the sensitized material, both with Pt./Pd. and with carbon. And even if one were to use a piece of mylar between the negative and sensitized material the pressure would suck moisture out of the material and adhere it to the mylar. I have experienced both of these things even with pressure at between 15-20 inches of mercury.

Sandy

 

[donbga]

Yes, I do pull it to 25" of Hg. There is anecdotal evidence to suggest higher vacuum increases separation of the high values. PM me if you would like to discuss this obscure observation in more detail.

Why not discuss this publically? I'm very curious. I'm not disputing what you suggest, I'd just like to learn more.

 

[juanito]

I use 21 inches of pressure. I use pictorico for pt/pd and I haven't had any problems such as you describe. The ink side of my negatives are in direct contact with the emulsion.

 

[sanking]

I use 21 inches of pressure. I use pictorico for pt/pd and I haven't had any problems such as you describe. The ink side of my negatives are in direct contact with the emulsion.

Are you working in Mexico City? If so your climate is very dry. The problem is one that happens when the sensitized material is wet or humid, either naturally in conditions of high humidity, or from humidifying to increase Dmax as some people do with Pt./Pd.


Sandy

 

[juanito]

Yes, I'm working in Mexico city and humidity is not a problem here. It's good to know what can happen when working in high humidity environement.
Thank you

 

[Joe Lipka]

I bow to the collective wisdom that is APUG. After confirming that there were no fuses of any type in the UV light box, I unbundled all the black wires, straightened them out and then re-twisted them into a nice bunch. I did the same for the white wires. SAFETY NOTE: I then plugged in the unit and all the bulbs lit up. Thanks for the assistance APUG. You have saved the Alt process print exchange.

 

[Bob F.]

Sounds like a loose connection then Joe - check all the terminal screws holding those wires in place.

Cheers, Bob.

 

[BrianShaw]

SOmetimes for an unknown reason my grounding doesn't cause the bulbs to ignite. I just reach in and run the back of my hand over the tubes and they light.

Is this a miracle or the gift of healing? Have you tried running the back of your hand over a sick person?