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  1. #11
    bobfowler's Avatar
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    If it's a common flash (such as a Vivitar 283), you might be able to get a factory repair manual with circuit diagrams, test point voltages, and other helpful info.

    The main flash cap of a rather small (50 watt second) on-camera flash can pack a hell of a whallop!
    Bob Fowler
    fowler@verizon.net
    Some people are like Slinkies. They're really good for nothing, but they still bring a smile to your face when you push them down a flight of stairs.

  2. #12

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    I have a knuckle that still can predict the weather 5 years after a 450V 1100uf zap. I got hit index finger to thumb. The cap was about 100V over design voltage due to a charging circuit problem.

    283s are pretty simple to take apart and fix. The things most likely to fail are the bulb (easy fix) and chopper transistor (not hard, but the transistor used on earlier models is no longer available anywhere. If you really need one I've got a stash that probably exceeds my lifetime requirements). Zoom head flashes are mechanically a lot more difficult a get apart and back together properly.

    Modern TTL flashes are pretty unlikely to be easily repairable.

    There's almost certainly not enough money in fixing old flashes to make a career or even paying hobby.

    The safe way to discharge a cap is with insulated clip leads and high-wattage resistors. My regime is a 5W 47K for 5 minutes, 5W 4.7K for 5 minutes, 5W 470ohm for 5 minutes, then (old) screwdriver short.

    DO NOT just short a fully-charged cap. It will take a chunk out of the screwdriver, make a noise that's a good imitation of gunfire, and likely damage the capacitor too.

    One neat thing you can do to a 283 is hook up an external battery pack, yank out the battery compartment and put in a second capacitor "donated" by another flash for an easy doubling of your power output. Hard on tubes though.

  3. #13

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    Quote Originally Posted by Roger Krueger

    The safe way to discharge a cap is with insulated clip leads and high-wattage resistors. My regime is a 5W 47K for 5 minutes, 5W 4.7K for 5 minutes, 5W 470ohm for 5 minutes, then (old) screwdriver short.
    Geez, it takes that much to totally discharge a unit?

  4. #14
    bobfowler's Avatar
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    Quote Originally Posted by Roger Krueger
    <snip>The safe way to discharge a cap is with insulated clip leads and high-wattage resistors. My regime is a 5W 47K for 5 minutes, 5W 4.7K for 5 minutes, 5W 470ohm for 5 minutes, then (old) screwdriver short.
    Excellent advice. Better safe than zapped.

    DO NOT just short a fully-charged cap. It will take a chunk out of the screwdriver, make a noise that's a good imitation of gunfire, and likely damage the capacitor too.
    Yeah, but it's sooooo much fun to arc weld!

    One neat thing you can do to a 283 is hook up an external battery pack, yank out the battery compartment and put in a second capacitor "donated" by another flash for an easy doubling of your power output. Hard on tubes though.
    Yup, that's what they did when they made Armatar units, except they put a Lumedyne flashtube in a box on top of the head. The spec sheet says it's a 300WS unit, and judging from the pop, it's pretty damn close! I love to use mine bare-bulb at wedding receptions - EVERYBODY gets "blue dot" syndrome!
    Bob Fowler
    fowler@verizon.net
    Some people are like Slinkies. They're really good for nothing, but they still bring a smile to your face when you push them down a flight of stairs.

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