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  1. #1

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    Preparing to convert SRT to Silver oxide

    Hi All,
    And In My search I haven't found a source for single Schottky Diodes used to reduce voltage! Anyone know of any source for them I can't afford to have 30,000 made and sit on them till they hatch!!:-) Or should I just go with the expensive alternitive wien cell battery? Any one out there use those tell me how long they last in use? It's always sumpthin'!! Or should or could I just have the meter in the SRT calabrated to use the 1.55 volts of the Silver oxide battery? Or is there a problem with doing that my brain damaged mind has failed to see?
    ALSO Anyone Know if a Minolta XD11 calabrated to use alkaline bateries at 1.5 volts would have a messed up metter IF one used the proper Silver oxide batteries in it at 1.55 volts? Or is this the wrong place for these questions???
    I'm sorry about my spelling also my phoenetics sucs! :-)

    Terry
    Terry
    I'm brain damaged,what's your excuse?

  2. #2
    Steve Smith's Avatar
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    I can probably find some BAT54 diodes I could send you. They are surface mount SOT23 package but I could add some wires to them.

    Datasheet here: http://www.fairchildsemi.com/ds/BA/BAT54.pdf

    If you want some, send me your postal address by PM.



    Steve.
    "People who say things won't work are a dime a dozen. People who figure out how to make things work are worth a fortune" - Dave Rat.

  3. #3
    bsdunek's Avatar
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    I use Wein cells in my Nikon FTN's and Gossen meters. They last nearly a year - depending on use. I buy them by the carton of 12 from Micro Tools. I think this is the easiest replacement for the PX13 & 625.
    http://www.micro-tools.com/store/ite...Code=MRB625-12
    Bruce

    Moma don't take my Kodachrome away!
    Oops, Kodak just did!
    For all practical purposes, they've taken Kodak away.


    BruceCSdunekPhotography.zenfolio.com

  4. #4
    Ralph Javins's Avatar
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    Good morning, Terry;

    The Silver-Oxide batteries have a much more stable discharge curve. Their voltage stays nearly the same over their useful life. Not exactly, but similar to the old Mercury battery, but at a slightly higher voltage. The alkaline batteries will have a constantly decreasing voltage that will affect the light meter reading by a constantly changing amount. At least with the Wien cells and the Silver-Oxide batteries, if the light meter reading is off, it will be off by a fairly predictable amount, so you can compensate if required. Often the lightmeter circuit can be adjusted to work with the 1.55 VDC batteries.

    There are many sources for Schottky Barrier Diodes. Radio Shack did have them in the past. Jameco Electronics. Digikey. All Electronics Corporation. RF Parts. Mouser Electronics. Ocean State Electronics. Frye's Electronics. Newark Electronics is still there, but the minimum order amount may not be palatable. There are still people who are selling bits and pieces.
    Enjoy;

    Ralph Javins, Latte Land, Washington

    When they ask you; "How many Mega Pixels you got in your camera?"
    just tell them; "I use activated silver bromide crystals tor my image storage media."

  5. #5

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    That doesn't look like the Diode listed in the srt pages at the Rokker something? My brain damage just kick in big time can't remember the name of the site now but they have the mod to silver oxide and it lists 1n7511 Schokkty Diode? Maybe what you have does something differently? What do I know? I get to know IF your pieces would work to lower voltage from 1.55 to 1.35 I'm all eyes!! :-) Interested that is Kind sir!
    Have a good one,
    terry
    Terry
    I'm brain damaged,what's your excuse?

  6. #6
    Nicholas Lindan's Avatar
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    Try looking for an 1n5711 Schottky... http://search.digikey.com/scripts/Dk...=497-2499-1-ND $0.46 each.
    Last edited by Nicholas Lindan; 11-26-2008 at 07:40 PM. Click to view previous post history.
    DARKROOM AUTOMATION
    f-Stop Timers - Enlarging Meters
    http://www.darkroomautomation.com/da-main.htm

  7. #7
    chriscrawfordphoto's Avatar
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    Quote Originally Posted by Nicholas Lindan View Post
    Try looking for an 1n5711 Schottky... http://search.digikey.com/scripts/Dk...=497-2499-1-ND $0.46 each.
    Thanks for the info. I had been looking for those, and every place I found wanted to sell 1000 of them at a time. Radio Shack didn't carry any of the ones that work for cameras. I just ordered a pack from Digikey.
    Chris Crawford
    Fine Art Photography of Indiana and other places no one else photographs.

    http://www.chriscrawfordphoto.com

    My Tested Developing Times with the films and developers I use

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    Fort Wayne, Indiana

  8. #8
    Steve Smith's Avatar
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    Quote Originally Posted by Terry Again View Post
    I get to know IF your pieces would work to lower voltage from 1.55 to 1.35 I'm all eyes!!
    The BAT54 drops just under 0.2v at minimal currrent. The one I measured was 0.196v so would be ideal.

    I have some here with wires attached and encapsulated in a bit of heat shrink tubing if you want them.


    Steve.
    "People who say things won't work are a dime a dozen. People who figure out how to make things work are worth a fortune" - Dave Rat.

  9. #9

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    Hi All,
    Steve I thank you for your kind offer and I think I shall see what happens on this side of the pond first? I still have to thank Nick for the link at Digi key that I missed while there!! Next is the 47 dollars shipping and handling charges!! It's the American Way!! And I still have to find and compare the discharge voltchange on the Silver oxide as compared to the wein cell ones? And find out the cost of the diode mod to the camera etc........ to make a true comparasion between the 2 types? And how long each kind last in use? Anyone out there in Minolta users land know? I thank you all for the replies on this question!!
    Terry
    I'm brain damaged,what's your excuse?

  10. #10

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    Terry,
    I did this mod to my SRT's some time ago (using the quoted IN5711 diode which I obtained off ebay) and it works great using silver oxide cells.I find silver oxide cells best - I find they last between 3 and 5 years in my SRT.Here is a link to the SRT battery mod at Anthony Hands' Rokkor Files
    site.In the first section there is a graph showing discharge profiles of the different types of cell.
    http://www.rokkorfiles.com/Dickspages.htm
    Hope this is useful.
    Rod Downes

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