Double Action switch repair

Discussion in 'Technical Repair' started by David121, Nov 5, 2016.

  1. David121

    Thread Starter New Member

    Nov 5, 2016
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    First off, I'm not an electronic expert in any way!
    I have a film camera from the early 1990's that has a weak shutter switch. It is a double action switch that has contacts that oxidise (not sure why, the camera forums say it is badly designed..., I wouldn't know!).
    This causes the camera to malfunction on a regular basis. However, it is fairly easy to access the switch and to take it apart (very gently!!) and clean the contacts with cleaner and a microfibre cloth.
    This allows the camera to function as normal for a while before it starts malfunctioning again.
    Sadly, the switch is no longer available, nor is there a similar sized switch available on the market that could be used as replacement.
    Now, the question.... Would it be possible, or any use, to coat the existing contacts with gold so that any oxidisation is still conductive. If this would work, how could it be done?

    Alternatively, where could I go to get a modern double action switch mounted on a 10mm by 10mm pcb with added lugs to enable it to be soldered to the existing pcb contacts. The existing pcb is a bendy brown plastic, not a solid board. In effect creating a replacement switch using a modern tiny d/a switch on a pcb to make it the same size as the older, larger, dodgy switch.

    If anyone out there fancies a crack at finding a solution there will be many, many grateful owners of these cameras!

    Thanks for your time. My fingers are crossed and my breath is bated.....
    I'm based in Northern Ireland but very often travelling around the UK.

    David
     
  2. Alec_t

    AAC Fanatic!

    Sep 17, 2013
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    Gold plating is worth trying. Gold plating solution is sold, but it's not cheap.
     
  3. RichardO

    Late Member

    May 4, 2013
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    Last I looked, Digi-Key sold switches like used for camera shutters. I can't remember if they were through-hole or surface mount. Which is yours?
     
  4. David121

    Thread Starter New Member

    Nov 5, 2016
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    I was hoping I could buy a modern equivalent, even if a slightly different size, but no-one does one remotely similar. There are a few momentary switches of similar size but no double action ones. Not that I can find on the interweb, anyway!
    All the others are miniature. There was a suggestion to place a miniature d/a tact switch in the old base and wire it accordingly, but what size wires to use? I have a few modern miniature switches that would work but I won't attempt soldering at that tiny scale!
    Unless there is a willing electronics wizard here in NI?
     
  5. RichardO

    Late Member

    May 4, 2013
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    Maybe this one. It is hard to tell from the data sheet. It is real big.
    http://www.digikey.com/product-detail/en/judco-manufacturing-inc/50-0088-00/542PB-ND/935975
     
  6. David121

    Thread Starter New Member

    Nov 5, 2016
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    Yes far too big RicardO, and the switching is wrong. Had a look through digikey and nothing else seems to be anywhere near similar.
    How could I go about getting one made? I realise I would need to order a load of them but might be worth it if the price is right. I could sell the rest to all the other owners with the same problem!
    Thanks for the interest though!
     
  7. RichardO

    Late Member

    May 4, 2013
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    Can you post a picture of the bad switch? Make sure that there is something in the picture to indicate scale.

    This might be called either a 2 or 3 position tactile push button switch. By the way, that switch is an OFF (ON) (ON) configuration. This means that it is normally off and is momentary on in 2 positions.

    A load of them might be like 10,000 but more likely 1,000,000.
    Can you post a picture of the bad switch? Make sure that there is something in the picture to indicate scale.

    This might be called either a 2 or 3 position tactile push button switch. By the way, that switch is an OFF (ON) (ON) configuration. This means that it is normally off and is momentary on in 2 positions.

    A load of them might be like 10,000 but more likely 1,000,000. :(
    Obviously they are made in these quantities for digital cameras. One possible manufacturer is Alps. Note that Alps won't even talk to you for quantities less than hundreds of thousands for _standard_ parts. :(:(

    Here is a table of Alps tact switches. The ones you are interested in are the "Double Action" ones -- but you knew that.
    http://www.alps.com/prod/info/E/HTML/Tact/SurfaceMount/SurfaceMount_list1.html

    Here is the smallest one from the Alps table. It has a chance of working. Mouser has some in stock:
    http://www.mouser.com/ProductDetail...ha2pyFaduigZUx497GD4M5XLlbgU01WHA1v%2b8rUSmg=

    Mouser has more of these -- they are cheaper but bigger:
    http://www.mouser.com/ALPS/Electrom...tches/_/N-5g2m?P=1z0zlgm&Keyword=sksd&FS=True

    And finally, the biggest and cheapest:
    http://www.mouser.com/Search/Refine.aspx?Keyword=skrn
     
  8. David121

    Thread Starter New Member

    Nov 5, 2016
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  9. David121

    Thread Starter New Member

    Nov 5, 2016
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    I found the same switches you did when I was looking for replacements. The nearest in size was the ALPS one sold by Mouser. I bought a few of them and one of the attached pics shows it placed on top of the original base. I guess it could be wired to the existing contacts but what sort of easy/hard job would that be? I've done soldering but not that tiny!
    Other pics show the original switch as is, and disassembled for cleaning.

    David
     
  10. David121

    Thread Starter New Member

    Nov 5, 2016
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    Or take the ALPS switch, mount it onto a 10mm x 10mm pcb, etched to match the new switch circuit to the existing contact points, add lugs and solder it in as a replacement.
    The new ALPS switch is smaller and thinner, but adding a pcb and solder lugs would make it thicker to match the dimensions of the original switch. I would need to do some careful measuring of course, but how to find a company that would make up this assembly?
    I could order enough to make it worth their while and sell the others to other owners of the same camera.
    I suppose it would mean careful measuring, a detailed drawing, and start phoning/emailing around!!!

    David
     
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