FrankS
Registered User
Those were in Canadian $, so that would be what, $3.50 US? 🙂
mercury battery adaptors
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RicardoD
Well-known
I used my "converted" Gossen Luna Pro today with my Yashica Mat 124G. My Yashica Mat meter and the Luna Pro were reporting the same exposure (metering in flat light, overcast skies) so it was a nice feeling knowing the in camera meter is working properly. I'm in heaven with these two devices. I think I took a nice portrait of my 4 yr old son in a Soccer uniform holding the brand new size 3 soccer ball I just purchased for him. Its a replica of what they are using in the World Cup now.
"This post is brought to you by the Silver Oxide batteries in my Luna Pro"
"This post is brought to you by the Silver Oxide batteries in my Luna Pro"
P
Pecker
Guest
When I saw the handwriting on the wall I hoarded every mercury battery I could get my hands on from eBay, and received more e-mail from the Eco-Nazis than you can imagine (apparently if the earth should self-destruct any time soon I apparently will be the major cause of it with the two dozen or so mercury batteries I have stored in my fridge). I wonder if we will ever see a return to reason; as pollutants are my mercury batteries on par with the coal fired power plants? Just curious...
FrankS
Registered User
I got my LunaSix 3 fixed today with Victor's diode gift! I'm a happyguy.
nikola
Well-known
hi, i'm quite perplexed....
...just bought online lunasix 3, and surfing around to find best replacement solution for mercury batteries....
chris is using silicon diode, but C.R.I.S. adapter and Gossen original adapter are using schottky diodes... and i know that their voltage drop is variable with load? so no stable 1,35V? is it really relevant for lunasix, does it have significant load variance so it is relevant?
what's the difference between using silicon and schottky diode?
how about recalibrating lightmeter to natively use SilverOxide cells?
...just bought online lunasix 3, and surfing around to find best replacement solution for mercury batteries....
chris is using silicon diode, but C.R.I.S. adapter and Gossen original adapter are using schottky diodes... and i know that their voltage drop is variable with load? so no stable 1,35V? is it really relevant for lunasix, does it have significant load variance so it is relevant?
what's the difference between using silicon and schottky diode?
how about recalibrating lightmeter to natively use SilverOxide cells?
ChrisN
Striving
Hi Nikola
I'm not an electrical engineer, and I don't really understand the difference between the two types of diodes. I worked from the information provided by others - see post #25 earlier in this thread.
As to simply recalibrating - well you could try it, but I found I didn't have enough adjustment available, and I suspect that the relationship between the lighting level and the meter movement would not remain true.
I'm not an electrical engineer, and I don't really understand the difference between the two types of diodes. I worked from the information provided by others - see post #25 earlier in this thread.
As to simply recalibrating - well you could try it, but I found I didn't have enough adjustment available, and I suspect that the relationship between the lighting level and the meter movement would not remain true.
nikola
Well-known
i have problem with doing things without real understanding 🙂
...but i'll force myself 😀
...but i'll force myself 😀
Bill58
Native Texan
You can certainly have your meter recalibrated but I chose the Kanto adapters because I have too many old RFs and the Adapter route was the most economical.
ErnestoJL
Well-known
The difference between Schottky and silicon is that Schotky diodes have a nominal drop of 0.2 V aprox, meanwhile silicon drop is aprox. 0.5 to 0.7 volts.
Other way to drop 0.2 volts is using the base-emitter junction of any small signal germanium transistor. You have to buy several and check for one that´s closer to 0.2 V drop.
Check also in google for "mercury battery replacement". Some time ago I found a nice page which had schematics for a low voltage drop active regulator able to reduce 1.5 V to 1.35 V. I think it can be modified easily to handle a higher drop from 3 V to 2.7 at small currents of up to a few mA.
Hope this helps a little.
Cheers
Ernesto
Other way to drop 0.2 volts is using the base-emitter junction of any small signal germanium transistor. You have to buy several and check for one that´s closer to 0.2 V drop.
Check also in google for "mercury battery replacement". Some time ago I found a nice page which had schematics for a low voltage drop active regulator able to reduce 1.5 V to 1.35 V. I think it can be modified easily to handle a higher drop from 3 V to 2.7 at small currents of up to a few mA.
Hope this helps a little.
Cheers
Ernesto
nikola
Well-known
heh, now what type of SilverOxide batteries to buy...
on Durcell site.. here
there are 3 high capacity batteries D303/357 (D357 goes into originall Gossen adapter), D301/386 and MS76, otheres have smaller capacity, does it matter until dimensions are ok (smaller life expectancy?) ?
and Varta V13GS, V76PX, V357.
V301, v386, v12gs, (height is 4,2mm all others are 5,4)
??? 😀
on Durcell site.. here
there are 3 high capacity batteries D303/357 (D357 goes into originall Gossen adapter), D301/386 and MS76, otheres have smaller capacity, does it matter until dimensions are ok (smaller life expectancy?) ?
and Varta V13GS, V76PX, V357.
V301, v386, v12gs, (height is 4,2mm all others are 5,4)
??? 😀
ErnestoJL
Well-known
Current consumption of a Lunasix (or LunaPro) is not higher to 2 mA in case of measuring high lights in both ranges (worst consumption situation). High/Low range switching is done optically instead of electrically. Then any battery that´s listed as possible replacement is OK, provided shape and size is compatible. Usually those listings show batteries which current capacity is equal to or a little higher than the battery it replaces.
Other thing to have in mind (and of capital importance) is to check (and if possible compare with the original mercury types) the battery discharge curves, it is voltage vs. time and voltage vs. current delivered. Then you can calculate with some accuracy (allways thinking of the worst condition) life expectancy of the batteries, and possibly also when the meter would yield a higher than expected measuring error.
Fortunately, silver oxide batteries have a discharge curve closer in shape to those mercury types, than alkaline batteries, it is the voltage is more stable vs. time. Also, for the same physical size, current capacity is a bit higher in silver than in mercury.
Hope this helps.
Cheers
Ernesto
Other thing to have in mind (and of capital importance) is to check (and if possible compare with the original mercury types) the battery discharge curves, it is voltage vs. time and voltage vs. current delivered. Then you can calculate with some accuracy (allways thinking of the worst condition) life expectancy of the batteries, and possibly also when the meter would yield a higher than expected measuring error.
Fortunately, silver oxide batteries have a discharge curve closer in shape to those mercury types, than alkaline batteries, it is the voltage is more stable vs. time. Also, for the same physical size, current capacity is a bit higher in silver than in mercury.
Hope this helps.
Cheers
Ernesto
BobFlyer
Newbie
Gossen Luna Pro
Gossen Luna Pro
I have installed the IN4148 pre the direction above. The battery check with fresh 357s falls just at the high side of the red zone. However, the meter when compared to my Minolta thru the lens metering is off by at least one stop, and more in lower light. Upon close inspection, since I had the unit open, the diffuser (silvery item that slides back and forth in front of the light collector) appears to have degenerated over the years, I can see where alot of pin holes that is allowing perhaps more light than required.
I am not sure if the meter is repairable? It is been the family for the past two generations. My dad owned the unit, an just recently I gave it a try, only to run into the common battery problem.
Is there anyone that could be recommended as a repair source?
Here is what I have tried.
Tried the Wein cells prior to modification, off by 2 stops battery check fall on next black left side on the left edge. Cells measured 1.4volts each no load
Tried(borrowed a gossen 4145 kit from a friend with fresh sr44 batteries) this was 3 stops off. Battery check ends up in the left side of the next black (to the right of the red) cells measured 1.61 volts each no load
Installed as a last resort the IN4145 with 357 batteries, It is closer 1 stop but appears to be very non-linear over the scale, dark to bright subjects, the bright subjects are almost within tolerance..Battery check is almost to the right side of the red battery check. I checked the voltage drop of the diode in a small circuit consisting of a 10k resistor the 1n4148 with a 1.5v battery, picked over the lot of 1n4148s looking for a unit that was dropping close to .5volts, the unit I ended up installing dropped .484volts. The 357 measured 1.55volts each no load.
I had adjusted the zero function per the instruction manual..prior to all of the above.
It is kind of bulky carrying around my trusted Minolta 7000 with ttl metering for my Mamiya TLR medium format camera.
New meters are quite expensive from just looking over the offerings.
My only thought was to try and buy a used Luna-pro and hope the diffuser is better than the unit I have, If that is really the problem. But this approach is not very good, since I would not have a clue as to the condition of the used meter..Ug.
The meter had never been opened up till today.
BobFlyer
Any comments appreciated..
Gossen Luna Pro
I have installed the IN4148 pre the direction above. The battery check with fresh 357s falls just at the high side of the red zone. However, the meter when compared to my Minolta thru the lens metering is off by at least one stop, and more in lower light. Upon close inspection, since I had the unit open, the diffuser (silvery item that slides back and forth in front of the light collector) appears to have degenerated over the years, I can see where alot of pin holes that is allowing perhaps more light than required.
I am not sure if the meter is repairable? It is been the family for the past two generations. My dad owned the unit, an just recently I gave it a try, only to run into the common battery problem.
Is there anyone that could be recommended as a repair source?
Here is what I have tried.
Tried the Wein cells prior to modification, off by 2 stops battery check fall on next black left side on the left edge. Cells measured 1.4volts each no load
Tried(borrowed a gossen 4145 kit from a friend with fresh sr44 batteries) this was 3 stops off. Battery check ends up in the left side of the next black (to the right of the red) cells measured 1.61 volts each no load
Installed as a last resort the IN4145 with 357 batteries, It is closer 1 stop but appears to be very non-linear over the scale, dark to bright subjects, the bright subjects are almost within tolerance..Battery check is almost to the right side of the red battery check. I checked the voltage drop of the diode in a small circuit consisting of a 10k resistor the 1n4148 with a 1.5v battery, picked over the lot of 1n4148s looking for a unit that was dropping close to .5volts, the unit I ended up installing dropped .484volts. The 357 measured 1.55volts each no load.
I had adjusted the zero function per the instruction manual..prior to all of the above.
It is kind of bulky carrying around my trusted Minolta 7000 with ttl metering for my Mamiya TLR medium format camera.
New meters are quite expensive from just looking over the offerings.
My only thought was to try and buy a used Luna-pro and hope the diffuser is better than the unit I have, If that is really the problem. But this approach is not very good, since I would not have a clue as to the condition of the used meter..Ug.
The meter had never been opened up till today.
BobFlyer
Any comments appreciated..
Last edited:
venchka
Veteran
BobFlyer said:
Weston Master V in good working order on ebay. That's what I did. In my case, to replace one I had ages ago and always regretted selling. No batteries! I understand that the cells can still be replaced.
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