Older Pentax Spotmeter

Discussion in 'Exposure Discussion' started by Nancy, Oct 17, 2006.

  1. Nancy

    Nancy Member

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    I think I probably just wasted my money, but if anyone can tell me different I'd really appreciate your input.
    I recently picked up what I thought was a bargain, a Pentax 1/21 analog spotmeter. It came with a working 9-volt (?) battery and it seems to work okay for the lower light exposures, but I don't have and can't find a 1.3 volt battery.
    I've searched and searched and of course have now discovered that the 1.3v battery is no longer made.
    Does anyone have this meter and have you found a substitute battery or work-around to the battery issue?
     
  2. Eric Rose

    Eric Rose Subscriber

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    I have the same meter and have no problems finding batteries for it up here in Canada. It's a great meter and out performs my fancy dancy super bucks digital meters in very low light. Basically any battery that you can find that is 1.3v and will fit into the compartment will work. If you have to go to 1.5 volts no biggy, just use the little adjustment screw to calibrate it. One thing that is very handy to have is a little thing called the Expo Disk. I have one and always make sure my meters are calibrated before a days shooting.
     
  3. Zathras

    Zathras Subscriber

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    Hi Nancy,

    Could you give us a little more info on which battery the 1.3 volt battery is. If it is something like PX-13 or PX-625, then you're in luck. There is an adaptor that will accept a 1.5 volt silver oxide battery that drops the voltage going into the meter to 1.3 or 1.35 volts. Go to http://www.criscam.com and check out the MR-9 adapter. I have one of these in my Canonet for those times when I need to use an autoexposure camera and it works beautifully.

    Hope this helps,

    Mike Sullivan
     
  4. Nancy

    Nancy Member

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    The (non-working) battery that came in the meter is an EPX640.
     
  5. Nancy

    Nancy Member

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    Oh, and I looked at the mr-9 adapter, but it looks like it's a thinner battery than the one I have that fits in the meter.
     
  6. resummerfield

    resummerfield Subscriber

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    The Mercury 640 battery (1.35 v) is no longer available. The Alkaline RM640 (1.5v) is commonly sold as a replacement. In theory, the extra voltage will require an adjustment, and the alkaline battery will not perform as well over its lifetime. Or, you may be able to fit a PX625 sized adapter into the battery compartment (use a metal shim to make-up the difference in thickness), and use the very common S76 cells. I have used the adapters shown in this link http://www.butkus.org/chinon/batt-adapt-us.pdf

    I used to have a Pentax 1/21, and it is a very nice meter, and well worth the effort to find a solution.
     
  7. dancqu

    dancqu Member

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    Mercury no longer. I've purchased WeinCell 1.35 volt
    zinc/air cells. I understand they are good for years.
    They are activated when placed in use. They fit
    just like the old mercuries. Dan
     
  8. John Koehrer

    John Koehrer Subscriber

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    PX13 & 625's are not the same size as the 640.
    You may check with Radio Shack to see if they have an equivalent in their catalog. Another option might be to import one from one of our Canadian friends which is most likely illegal.
    So many choices.
     
  9. MattKing

    MattKing Subscriber

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    Sorry - no mercury batteries allowed in Canada either.

    Matt
     
  10. Nancy

    Nancy Member

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    Thank you all for your suggestions. I'm going to take a look at radio shack and if I don't come up with anything I'll send the meter to my father (along with the info you've shared). He's pretty good with this sort of thing so I'll see what he can come up with.
     
  11. garri

    garri Member

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  12. epatsellis

    epatsellis Member

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    I use zinc air cells with an o-ring to make the diameter larger, cost effective too!

    erie