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Message |
    
Wermworm
Tinkerer
Username: Wermworm
Post Number: 1
Registered: 08-2013
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, August 07, 2013 - 12:41 pm: | 
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Hello good people.
I have an old IKOPHOT lightmeter that is "dead". Upon opening it and messing around with it I was able to see that it does work sometimes, mainly when it wants to or when i'm pressing a particular piece of the insides (not the same piece everytime), so i'm kind of lost as what to do in order to fix it (if possible at all).
Can anyone help me?
thank you |
Mr_flibble
Tinkerer
Username: Mr_flibble
Post Number: 117
Registered: 10-2011
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, August 07, 2013 - 01:24 pm: |
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The early light meter electronics consist of a single circuit, constisting of a selenium cell, a resistor and the gauge, not much else.
If it works sometimes as you say, it sounds like a loose wire somewhere. |
Denny
Tinkerer
Username: Denny
Post Number: 147
Registered: 08-2009
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, August 07, 2013 - 08:24 pm: |
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On some old selenium cell meters, the selenium cell has tabs that basically make contact by a spring action. The surfaces of the "spring contact area" oxidize and cleaning them will restore a stable contact. This is sort of why the "thump" method sometimes works, but I ain't goin' there  |
Michael_linn
Tinkerer
Username: Michael_linn
Post Number: 96
Registered: 04-2011
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, August 07, 2013 - 11:23 pm: |
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I agree with Denny.
Just get inside and clean it up. There is a good chance it will work like new.
Mine does, and it's cute, too. |
Wermworm
Tinkerer
Username: Wermworm
Post Number: 2
Registered: 08-2013
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, August 08, 2013 - 02:25 am: |
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Hey! thank you so much for the replys. What can I clean it with? I mean, with what material/liquid?
I know the cell has 2 lines (painted one at each side) of a silver color substance that makes contact with small metal pieces in front, these pieces then follow to a wire.
My first guess would be cleaning it up, but I am afraid I could make it worse by using the wrong materials.. |
Mr_flibble
Tinkerer
Username: Mr_flibble
Post Number: 120
Registered: 10-2011
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, August 08, 2013 - 06:46 am: |
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You can start by gently rubbing those two small metal contacts with the wires attached to them to clean off any visible oxidation. Carefully rub with a fine emery cloth if the oxidation is more extensive.
You can safely clean with q-tips and cleaning alcohol as the alcohol dries without leaving a mark.
Clean the two silvery contacts on the cell only if they are oxidized. If you damage the cell's external coating it will degrade rapidly. |
Denny
Tinkerer
Username: Denny
Post Number: 148
Registered: 08-2009
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, August 08, 2013 - 11:32 am: |
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I have used a pencil eraser and if that doesn't quite do it, then a q-tip soaked with CRC electronics cleaner. That stuff evaporates quicky and don't use CRC elecTRIC cleaner. It will dissolve plastic whereas, the elecTRONICS cleaner is safe for about everything. Good Luck. |
Wermworm
Tinkerer
Username: Wermworm
Post Number: 4
Registered: 08-2013
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, August 17, 2013 - 02:01 pm: |
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hello again! I finally got around to give another try at the lighmeter. I opened it and tried to clean it the best I could. The meter seems exactly the same as before. It reacts randomly. Sometimes when I apply pressure to a specific area, other times when I apply pressure to another area. But when I get it to "stay" and work well, when I put the cover on it stops working.
HEre are 2 pictures I took of its inside.
http://flic.kr/p/fw8NWz
http://flic.kr/p/fwo59s |
Br1078lum
Tinkerer
Username: Br1078lum
Post Number: 633
Registered: 11-2010
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, August 17, 2013 - 07:38 pm: |
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I'd like to help, but mine is a slightly different model (maybe just a few years older), and it seems to be glued into the leather case. Oh, and previous owner took the screws out of the diffuser panel, so I can't use that, either.
But from what I can see in your photos, your contacts on the cell are severely corroded. You might try getting some PC Board Trace to apply to the contacts, and hopefully increase their conductivity
PF |
Glenn
Tinkerer
Username: Glenn
Post Number: 1089
Registered: 07-2006
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, August 20, 2013 - 03:20 am: |
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Storing these meters in their original leather case is a death knell. The cases just act like a sponge unless the item is stored in a very dry atmosphere. Unless somebody has been bloody stupid, I doubt that Phil's case is 'glued on', damp, body oils and good old degradation have probably bonded the case to the plastic body.
This was the first meter I can remember my father using. It took me many tries, a few years back, to find a nice one to add to my collection as most were in the condition we see here - some even had tacky/sticky plastic bodies. |
Wermworm
Tinkerer
Username: Wermworm
Post Number: 5
Registered: 08-2013
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, August 21, 2013 - 09:23 am: |
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My case is borken in 2, you can see here - http://flic.kr/p/fwo64d
I havent hit the case yeat, my approach would probably be glue.. ?
Regarding the "PC Board Trace", english isnt my first language so I'm a bit lost on this, but Im guessing this is some kin d of "paste" like a toothpaste substance I aplly on the cantacts, is that it?
thank you |
Br1078lum
Tinkerer
Username: Br1078lum
Post Number: 636
Registered: 11-2010
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, August 21, 2013 - 08:07 pm: |
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It's a paint-on copper coating that is used to repair broken circuit traces on Printed Circuit (PC) boards, Werm. You can get it from electronics hobby shops, or online. I haven't bought any in a long while, so I'm not exactly sure what it's called.
PF |
