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New old light meter Gossen SIXON 2
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PostPosted: Sat Sep 15, 2007 6:35 pm    Post subject: New old light meter Gossen SIXON 2 Reply with quote

I've recovered my old lighmeter.
Unfortunately, the battery is out and I cannot test it. It was made of a CdS cell, so I have little expectations.



Besides this, the battery is one of those "extinct" ones, a PX625 one.

Best regards,
Jes.


PostPosted: Sat Sep 15, 2007 7:16 pm    Post subject: Reply with quote

Weincell.....

http://www.smallbattery.company.org.uk/

Or make up an adapter for SR44 silver oxide cells using the PDF instructions by Frans de Gruijter on this site:

http://www.paulbg.com/Nikon_F_meter_batteries.htm

Or buy one ready made...

Name: Frans de Gruijter
Email: battery.adapter@orange.nl
Location: Zuidkade 161
2741 JJ Waddinxveen
The Netherlands

Info: Designer of PX625 non-mercury battery adapters & kits


PostPosted: Sat Sep 15, 2007 8:35 pm    Post subject: Reply with quote

bob955i wrote:
Weincell.....

http://www.smallbattery.company.org.uk/

Or make up an adapter for SR44 silver oxide cells using the PDF instructions by Frans de Gruijter on this site:

http://www.paulbg.com/Nikon_F_meter_batteries.htm

Or buy one ready made...

Name: Frans de Gruijter
Email: battery.adapter@orange.nl
Location: Zuidkade 161
2741 JJ Waddinxveen
The Netherlands

Info: Designer of PX625 non-mercury battery adapters & kits

Bob, thanks a lot!
I love those diode tricks... Let's experiment!
Best regards,
Jes.


PostPosted: Sat Sep 15, 2007 11:58 pm    Post subject: Reply with quote

Up and running... It has an adjustmen knob on the backside that allows to work with batteries over than 1.35volt.
Now I've got a nice light meter Wink
Best regards,
Jes.


PostPosted: Sun Sep 16, 2007 9:23 am    Post subject: Reply with quote

It's best to use a silver oxide cell rather than alkaline as the silver oxide has a similar, though not identical, discharge rate to mercury, unlike alkaline which gradually drops.

What this means in practice is that with an alkaline cell, your meter will over-read to begin with, thus resulting in under-exposure, and as the cell discharges, it will reach a point where it will read correctly, and then as the cell voltage drops further, will under-read, giving you over-exposure.


PostPosted: Sun Sep 16, 2007 7:28 pm    Post subject: Reply with quote

bob955i wrote:
It's best to use a silver oxide cell rather than alkaline as the silver oxide has a similar, though not identical, discharge rate to mercury, unlike alkaline which gradually drops.

What this means in practice is that with an alkaline cell, your meter will over-read to begin with, thus resulting in under-exposure, and as the cell discharges, it will reach a point where it will read correctly, and then as the cell voltage drops further, will under-read, giving you over-exposure.


Ok, Bob, understood. I'll go for silver-oxide cells. Thanks for pointing it!.
On the other hand, I've been thinking on putting a voltage regulator inside the light meter (there is some room inside), so the variations on the battery voltage would be not relevant at all... But I don't have an schematic yet...
Silver oxide until a better solution.
Best regards,
Jes.


PostPosted: Sun Sep 16, 2007 8:18 pm    Post subject: Reply with quote

I was looking at a schematic the other day Jesito - I'll see if I can find it again. Smile


PostPosted: Sun Sep 16, 2007 9:16 pm    Post subject: Reply with quote

bob955i wrote:
I was looking at a schematic the other day Jesito - I'll see if I can find it again. Smile


Thanks! I think I got something in that line... Wink

http://www.sover.net/~snowleop/merc/

Well, it's not a schematic, but if someone has done it, should be workable!

Best regards,
Jes.


PostPosted: Mon Sep 17, 2007 5:20 pm    Post subject: Reply with quote

Here it is Jesito:

http://ludens.cl/Electron/mercreg/mercreg.html

Have fun... Wink


PostPosted: Mon Sep 17, 2007 6:06 pm    Post subject: Reply with quote

bob955i wrote:
Here it is Jesito:

http://ludens.cl/Electron/mercreg/mercreg.html

Have fun... Wink

Thanks!. A little clumsy to fit inside a battery holder with a smaller battery, but nice to try!.
Lots of fun... for sure!
Many thanks
Best regards,
Jes.


PostPosted: Mon Sep 17, 2007 7:11 pm    Post subject: Reply with quote

It's actually more a permanent feature for fitting somewhere inside the camera, rather than in the battery holder.


PostPosted: Mon Sep 17, 2007 9:24 pm    Post subject: Reply with quote

bob955i wrote:
It's actually more a permanent feature for fitting somewhere inside the camera, rather than in the battery holder.


True, it covers my two current needs, the lightmeter and the Konica C35.
Both should have room inside.
But I found a handful of 1,5 volt small batteries and I started to wonder how to fit the circuit in an adaptor... Full SMD.
I'll be doing bricolage in short.
Best regards,
Jes.


PostPosted: Mon Sep 17, 2007 9:45 pm    Post subject: Reply with quote

Wow - technobabble at its best. I am really impressed. I have a Zeiss Ikophot that is at least 40 years old uses a photocell and still works like a charm.


PostPosted: Tue Sep 18, 2007 5:37 pm    Post subject: Reply with quote

patrick wrote:
I have a Zeiss Ikophot that is at least 40 years old uses a photocell and still works like a charm.


Sometimes less is more - I have a 45 year old Rank Mamya 4B RF which has a selenium cell meter and it's still as accurate as my Gossen Lunasix 3 after all these years.

jesito wrote:
Full SMD.


If you're going to use SMD components throughout, you should just about be able to fit it all inside the full stop at the end of this sentence..... Wink Laughing


PostPosted: Tue Sep 18, 2007 9:19 pm    Post subject: Reply with quote

bob955i wrote:
Full SMD.

If you're going to use SMD components throughout, you should just about be able to fit it all inside the full stop at the end of this sentence..... Wink Laughing


Laughing Laughing Laughing

Jes.


PostPosted: Sat Sep 22, 2007 9:11 pm    Post subject: Reply with quote

bob955i wrote:
Here it is Jesito:

http://ludens.cl/Electron/mercreg/mercreg.html

Have fun... Wink


Just found another interesting circuits:

http://www.techlib.com/electronics/mercury.htm

Best regards,
Jes.


PostPosted: Mon Sep 24, 2007 11:53 pm    Post subject: Reply with quote

In the meantime to the final stabilized circuit, I've found at the optics shop some Zinc-Air batteries (that fit well to the Konica C35), and are not too expensive. They are 1.4 volt, so close enough to the 1.35 target to be useful. I've got 6 batteries for 7,5. Taking into account that they last for three month, I can enjoy the camera during the next year and a half whilst I build the voltage level adapter.
The Sixon seems to be happy with the SR44 that is 1.5volt. It can be tuned to the right position with this battery...

Best regards,
Jes.