Schottky fix for Gossen meter?

[Eric Dolphy]

hello will these batteries
http://www.amazon.com/Energizer-Silver-Oxide-Batteries-357/dp/B001977NCQ
work in this Gossen meter
http://www.jollinger.com/photo/meters/meters/gossen_lunapro.html
(to replace mercury batteries) --or, simply
shelve the meter

or, have you seen a Schottky DIY diode fix to keep the meter going thx all

​

 

[miha]

I'm using an adapter in my Leicaflex, works perfectly: http://www.butkus.org/chinon/batt-adapt-us.pdf

 

[Eric Dolphy]

thank you, Miha--that's the repair: kit approx $22, delivered...

...probably worth it, as I am told the meter is exceptional...approx $70 new in 1967: a fairly costly meter, it would seem.

here is another view of the repair:

http://gbchcf.free.fr/lunasix3.htm

here is another possibility: 675 zinc air, with 'spacer':

http://rick_oleson.tripod.com/index-111.html

one more:

http://www.bhphotovideo.com/c/product/89868-REG/Gossen_GO_4145_Adapter_Kit_Battery_Holder_for.html

 

[BrianShaw]

The options are all stated above but I suggest you just get the Gossen adapter. A lot less hassle than the alternatives. I've used one for many years. It is a sure life extension for Luna Pro... Which is a great meter.

 

[frank]

I modified my gossen meter with the diode. Less than 30 minutes. Basically free.

 

[mnemosyne]

I agree with Brian, the "official" Gossen adapter is the easiest / most convenient solution in this case. To avoid confusion, the Luna Pro model was called Lunasix 3 in the German market, so the adapter is ususally called "battery adapter for Lunasix 3/3s" here.

http://www.amazon.de/Gossen-Batteri...973626&sr=8-1&keywords=Gossen+Lunasix+Adapter

 

[Eric Dolphy]

once the adaptor is installed, is calibrating the old Gossen a DIY process--or, best sent to a shop thx all

 

[BrianShaw]

The only thing needed after installing the battery adapter is to verify the zero adjustment. and then start shooting!

 

[paul ron]

thank you, Miha--that's the repair: kit approx $22, delivered...

...probably worth it, as I am told the meter is exceptional...approx $70 new in 1967: a fairly costly meter, it would seem.

here is another view of the repair:

http://gbchcf.free.fr/lunasix3.htm

here is another possibility: 675 zinc air, with 'spacer':

http://rick_oleson.tripod.com/index-111.html

one more:

http://www.bhphotovideo.com/c/product/89868-REG/Gossen_GO_4145_Adapter_Kit_Battery_Holder_for.html

would anyone translate the french fix to find out which diode was used?

thanks

ive been using my luna pros with the alkaline batteries n never had any problems but i did spend alot of time calibrating my exposures, developing n printing so everything jives.

 

[BrianShaw]

would anyone translate the french fix to find out which diode was used?

thanks

ive been using my luna pros with the alkaline batteries n never had any problems but i did spend alot of time calibrating my exposures, developing n printing so everything jives.

https://translate.google.com/translate?hl=en&sl=fr&u=http://gbchcf.free.fr/lunasix3.htm&prev=search

 

[paul ron]

omg thats great!

thanks

 

[BrianShaw]

Yes, great... with one exception: I don't think the specific diode was ever specified.

 

[DWThomas]

Even in French I thought I saw the word "germanium" which produces a diode with a lower forward drop than silicon, but I think is pretty rare in today's semiconductors.


(Uh -- or maybe that was 'geranium'! )

 

[John Koehrer]

The PDF on Butkus(link above) gives a 1N4148 in series for each cell.
One cell=one diode, two cells=two diodes.
the complete instructions have everything you need to know. Well, about the diode anyway.
Since I'm a cheapskate and already have a soldering iron I'd do the diodes, it's 30euros less.

 

[Steve Smith]

A 1N4148 diuode gives about a 0.7 volt drop. These modifications usually specify a Schottly diode with a 0.2 volt drop.

A suitable part would be 1N5711.


Steve.

 

[paul ron]

i saw germanium n also assumed in4148 but the drop is rather steep. ill use the in5711.

 

[DWThomas]

Yeh, the germanium diode would be something like a 1N34a that we built "crystal radios" with back in the late bronze age. Purportedly there are still some around, but I would expect Schottky devices to be more reliable.

 

[paul ron]

hahaha no cat whiskers?

but if your voltage could use almost a volt drop then the germanium would do just fine.

 

[Steve Smith]

but if your voltage could use almost a volt drop then the germanium would do just fine.

That's too much. It needs to reduce the 1.5 volts of a modern cell down to the 1.3 volts it would have seen from a mercury cell.


Steve.

 

[DWThomas]

Of course in all cases there is a dependence on actual current levels, but as I remember it "back in the day," the nominal forward drop of typical germanium devices was 0.3 volts and silicon, 0.7. The big deal about Schottky devices was they had the better temperature range and lower reverse leakage typical of silicon devices combined with a lower forward voltage. A few tenths of a volt difference in a device carrying -- say -- 20 amps -- is quite a difference in power dissipation.

There is quite a detailed document on the Butkus site about some of the substitutions and conversions to replace mercury cells. EDIT: Already linked way back. Note it does not say a 1n4148 is a Schottky, it is a straight silicon switching diode (a classic, actually) and is saying it can be used to replace TWO Schottky diodes in a two cell circuit; it's all about the voltage drop.

Back when, I tried a CRIS adapter in my Gossen Super Pilot, but found the battery holder arrangement in the meter was a sort of mechanically sketchy affair that couldn't hold the adapter solidly enough to maintain reliable electrical contact. So I opened the meter and put a diode in. Don't know if it was the diode, or just "how it was," but the sucker was a total slug to come to a reading. I vaguely recall it was always slow, but had not used it in years, as my later cameras had built-in meters. So after some contemplation, I bought a Digisix -- and in a later GAS attack, a Sekonic L508! Problem solved -- throw money at it!