Time-O-Lite Discovery

Discussion in 'Darkroom Equipment' started by Vaughn, Jan 24, 2008.

  1. Vaughn

    Vaughn Subscriber

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    I take care of the teaching darkroom for a university. I have been having the enlarger bulbs blowing on me right and left on one of my banks of Beseler 23C enlargers for the past couple years. Sometimes several a day, then a long break. I was buying the bulbs 24 at a time several times a year. I had our electrician to put a voltage recorder on the curcuit, etc.

    But I think I discovered the problem this morning. I checked all the Time-O-Lite timers (Masters and Pros) and found one that throws about 400 to 500 volts back into the supply line just as it shuts off. So if someone on the same curcuit has their enlarger light on while this beast shuts off, it might be blowing the bulb with the power spike.

    Now the timer is engraved HSC and then a inventory number. The university changed its name from HSC to HSU in 1973...so this beast is at least 35 years old. I suppose it is amazing that it still works at all after 35 to 40 years of constant use (I have others of the same vintage that still work fine, and the back-up timer I put in its place is of the same vintage).

    Any electricians out there that might confirm my suspecions about the timer? The way I measure it was to put the timer on a two out-let extension cord. Plugged in the timer to one of the out-lets and put the meter's probes in the other...and watched the needle jump from 110V to about 500V as the timer shut off.

    Vaughn

    PS...the next question is if it is worthwhile to send it back to the factory to be repaired ($75 to $100 is the average repair bill, as per the company).
     
  2. Mike Kennedy

    Mike Kennedy Member

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    I have the same timer as a back up.Stumbled on a digital (pardon the lingo) Gralab last summer.Fantastic.
    IMO it wouldn't be worth your while to have it repaired.Maybe bronze it as a keepsake for it has served you well.
     
  3. Mike Kennedy

    Mike Kennedy Member

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    Here's the Gralab.

    Paid $15.00 at a yard sale.
     

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  4. Vaughn

    Vaughn Subscriber

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    Our other timers are Beseler Digital timers...they are alright, but I have to send them in for repairs regularly. We have 19 enlarger stations, 125 to 150 students per semester, and besides the class times, about 75 to 80 hours of open darkroom time a week. Those buttons get pushed a lot! And often with wet fingers.

    I am afraid the Gralab digitals would not hold up to the punishment.

    Vaughn
     
  5. ath

    ath Member

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    The timer might not be defect, it might just be the way it works. You might want to put an overvoltage protector / supressor on the powerline of the enlargers.
     
  6. Craig

    Craig Subscriber

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    They are surprisingly tough, we had one in my highschool yearbook darkroom and it never gave any trouble. Considering how cheap they can be bought these days if it lasts 3 years and then you replace it, its probably cheaper then changing bulbs.
     
  7. dpurdy

    dpurdy Member

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    I nailed one of those timeolite timers to the wall of the studio for timing polaroids. Great for that.

    For the darkroom the Beseler Audible Repeating timer is hard to beat.
     
  8. Chan Tran

    Chan Tran Member

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    What kind of heads do you have in your Beseler 23? I think the high voltage surge is not coming from the time-o-lite but rather the 23C which has a power supply.
     
  9. Vaughn

    Vaughn Subscriber

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    Ath -- I checked all our Time-O-Lites...it was the only one that sent a spike of high voltage back into the curcuit...I don't think it is suppose to do that (and I don't want any computer equipment on the curcuit either! LOL! The other Time-O-Lites gave no indication of any spike of any size...no movement of the needle of the voltmeter. But your idea of putting surge protectors on the enlargers is an interesting one. If the problem continues without the spiking timer on the curcuit, I'll give it some thought...though 8 surge protectors would not be cheap either.

    Dpurdy -- that is actually the Beseler timers we have. Good timers but the print buttons fail eventually in a teaching darkroom -- pressed too hard sometimes hundreds of times a day! And occasionally the contacts of the knobs used to set the times fail. And they are also $75 to $100 to repair.

    Vaughn
     
  10. dpurdy

    dpurdy Member

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    You could go old school and get a metronome. When I was in school at Glen Fishback in the 70s they had one Beth and Thomas metronome (you wouldn't want two) for the darkroom. Tic Tok Tic Tok Tic Tok. Everybody counts the seconds. To this day I count the beeps on my Beseler Audible. No one complained about the tic toc in school, but it was annoying that one guy would hum a tune in time.
     
  11. PHOTOTONE

    PHOTOTONE Member

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    I think you mean a SETH THOMAS (brand) METRONOME. Quite a common brand for Metronomes and for Clocks.
     
  12. dpurdy

    dpurdy Member

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    ha ha probably... hey I been hanging in darkroom fumes for 30 some years.
     
  13. Vaughn

    Vaughn Subscriber

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    A metronome...isn't that a little funny looking guy, but all sort of modern...you know, a well dressed gnome?

    Have you been in a darkroom full of 18 to 22 years olds lately? Either they have their iPods sticking in their ears or they have the CD player cranked up...no one will be able to hear a metronome (or a retrognome).

    Chan...some of these 23C's are as old as the timers...all condenser heads...nothing but the light bulb in there.

    Vaughn
     
  14. BradS

    BradS Subscriber

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    Vaughn,

    Interesting discovery. I have an old Time-O-Lite P-59 that, I swear, has a mind of its own. Seems to work fine, if a bit noisy, most of the time but every once in a while, it just kinda goes berserk! I wonder...?
     
  15. Deckled Edge

    Deckled Edge Member

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    The circuit board is not well supported near the print button, and the board begins to flex. Eventually no circuit when you push PRINT. I had to insert a little block of wood behind the board to bolster the support. Works again.
     
  16. Vaughn

    Vaughn Subscriber

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    Thanks DE...I'll haul out the 8 or so Beseler timers I have awaiting funds for repair and see it that works on some of them! I am all out of back-ups, and no money to send any off until the next budget cycle.

    Brad...I notice one enlarger not getting much use, so I checked it out -- the timer buzzed like a banshee. Probably had the students wetting their pants when they made their first test strip! I removed it from the darkroom, but haven't checked that one to see if it tosses out a few more volts than it is suppose to.

    Vaughn
     
  17. Nicholas Lindan

    Nicholas Lindan Advertiser Advertiser

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    That can also indicate a cracked trace on the circuit board or a cracked solder connection. The block pushing the board back up pushes the cracked bits together so they make contact again. It's a very common failure mode.
     
  18. Nicholas Lindan

    Nicholas Lindan Advertiser Advertiser

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    That was what drove me into the timer buisness -- opening up a failed Beseler timer to fix it and deciding there was a problem here that needed a much bigger fix.
     
  19. Mike Wilde

    Mike Wilde Member

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    Electrical engineer speak follows

    when a motor shuts off, all of the magnetic field (that causes the motor to spin) that was being created by the electric field collapses. Since the electric field was shut off, it is now able to take back energy that the magnetic field wants to dump. The magnetic field in most motors does not decay gradually, so the electriclk field does not absorb that magnetic energy gradually. It takes it in all one fast whump.

    A capacitor placed across a contact that shuts off a motor usually does the job of absorbing that 'whump' and storing the all at once energy, and then bleeding it out over a longer period fo that it is not so disruptive.

    I suspect that there is an open circuit 'squelch' capacitor in the offending time o lite. Replacing it, if this is the case is likely a 1 hour and $2 in parts repair.
     
  20. Vaughn

    Vaughn Subscriber

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    Thanks Mike. That probably entails soldering and all that fancy stuff, LOL! We'll see if I undertake such a project...electrical/electronic wimp that I am! I'd probably have to open the timer up and take in down to the next town's electrical/electronic supply store and ask them to point out the "open circuit 'squelch' capacitor" and see if they have one in stock. (and probably ask how much they would charge to replace it).

    If only my electrical engineer brother-in-law didn't live 800 miles away!

    Vaughn
     
  21. srs5694

    srs5694 Member

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    You could mail it to him. If he'd fix it for free, two-way postage would still be cheaper than an official repair.

    Another option: Since this is a university darkroom, there must be faculty, staff, or even students who are capable of doing such a repair pretty near by. You might be able to barter the repair for a couple of hand-made enlargements or get it done inexpensively in a university-run shop.
     
  22. MattKing

    MattKing Subscriber

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    For some reason, when I read the suggestion of a metronome, I thought you ment one metronome per enlarger.

    The image in my mind of a group darkroom, complete with a cacophony of metronomes, is somehow completely disturbing :smile:.

    Matt