monopix
Cam repairer
Yes, it is a bridge circuit.
The problem with the alkalines is the current they can deliver and, if it wasn't for the bridge circuit, they wouldn't work at all. You may find the battery check light doesn't work (or doesn't work for long) with the alkalines as the battery check is done on fixed voltage thresholds.
elwrongo
Established
Thanks for the diagrams. I will try this one day as it would be good to be able to use silver oxide cells. Its just the tiny soldering odf the tiny wires I'm afraid of. For the moment though I'll continue with zinc air 675 cells for most cameras and the PX28 plus tube and spring for the Electro 35. (I actually have an original fully charged mercury Panasonic HM-4N (like a PX32A) that came with an Electro GSN. But I daren't use it.
eliemarga
Member
I was curious watching your diagram and find several words I'm familiar with (e.g. solusi ) and realize we're coming from same country 
in some case is it possible to modify the battery chamber? sort of like making a battery adapter, but permanently/stay in the chamber...and yes, germanium isn't common and fairly rare in Indonesia.
I used to have SR44 in my camera and switched to 4x LR44 basically because it's the same battery, same voltage though I reckon SR44 deliver more stable voltage...some people used to joke that they've open SR44 and found out 4x LR44 stacked there....my dad second to that opinion, however I haven't proved that...SR44 is quite rare in my hometown
in some case is it possible to modify the battery chamber? sort of like making a battery adapter, but permanently/stay in the chamber...and yes, germanium isn't common and fairly rare in Indonesia.
I used to have SR44 in my camera and switched to 4x LR44 basically because it's the same battery, same voltage though I reckon SR44 deliver more stable voltage...some people used to joke that they've open SR44 and found out 4x LR44 stacked there....my dad second to that opinion, however I haven't proved that...SR44 is quite rare in my hometown
eliemarga
Member
basically with that kind of solution (spring and other metal) will give you false reading, but 'false' is rather subjective and fairly depend on photographer's taste...accurate reading by yashica's engineers might means 0 ev, but for me 0 ev is a little bit over expose, in result I always have all my photos taken at -1 ev to suit my taste...in your case it might be fine with your photo as it's what you comfortable with :angel:
monopix
Cam repairer
Why will this give a false reading?
eliemarga
Member
just my assumption that if you don't have the voltage delivered at the right value then the meter would behave differently, not?
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I apologize monopix, I miss read your reply up there about the current...so, the battery is basically needed to powered up the entire circuit and the voltage difference is fine as long as they're in the 'tolerance'? therefore, we might re-adjust how the meter will read by modifying the circuit eh? sorry I screw up the whole point up there :bang::bang:
in my case, I use 3v battery to power up the meter on my lynx 5000e and it reads 2-3 stops higher than my other camera, how to solve this if it's not about the battery
cheers
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monopix
Cam repairer
Not sure what you mean but no adjustment or modification of anything is required. The camera is very tolerant of voltage variations.
eliemarga
Member
I've ask joe wolff (yashica guy) and he pointed me out this
http://www.yashica-guy.com/document/lynxfix.html
it is mention there The solution to this problem is to disconnect the 5k resister, and to bridge the circuit with a variable resister, [potentiometer] with a maximum value of 5k, and then to adjust this down until the exposure readout is correct. The value can then be read, and the 'pot' can be replaced with a fixed resister of the indicated value
what do you think?
another source which also says about adjusting the meter is here:
http://www.mattdentonphoto.com/cameras/yashica_lynx_5000.html
The CdS meter is activated by a button on the front of the camera, and shows the over/under needle both on the top of the camera and in the viewfinder. The meter runs on an obsolete 1.3v mercury PX625 battery, but you can use a 1.5v alkaline and adjust the ASA to 1/2 actual to compensate, or use a 1.4v hearing aid battery and space it with a small #9 faucet O-ring if necessary.
In my case the battery is just for the meter, but in electro the battery will be used for the meter then it will decided the 'correct' shutter speed...I've tried what matt denton suggest which is to change the ASA setting in my lynx 5000e, I'm using 3volt battery while some manual said that 5000e needs 2.7volt battery...I tried to compare the reading from CdS meter and what I have in my dslr and in order to have both matched I had to change the ASA setting in my lynx from 200 (which is the film I use now) to 400, from there all the reading that I have in 5000e is exactly what I have in my dslr....however joe wolff added that, this is not the case of broken CdS, but because each camera manufacture has sets their own standard how the meter will read in such situation and this might or might not suit the taste of each owner (in my example, I tend to have my mg-1 and lynx 5000e have 2-3 stops over exposed compared to what I have in when I'm using with dslr, MG-1 is different but with lynx 5000e which is manual exposure camera, all setting in 5000e which is shown 'correct exposure' by CdS censor in the same condition is always 2-3 stops overexpose then what I have in my dslr)...
http://www.yashica-guy.com/document/lynxfix.html
it is mention there The solution to this problem is to disconnect the 5k resister, and to bridge the circuit with a variable resister, [potentiometer] with a maximum value of 5k, and then to adjust this down until the exposure readout is correct. The value can then be read, and the 'pot' can be replaced with a fixed resister of the indicated value
what do you think?
another source which also says about adjusting the meter is here:
http://www.mattdentonphoto.com/cameras/yashica_lynx_5000.html
The CdS meter is activated by a button on the front of the camera, and shows the over/under needle both on the top of the camera and in the viewfinder. The meter runs on an obsolete 1.3v mercury PX625 battery, but you can use a 1.5v alkaline and adjust the ASA to 1/2 actual to compensate, or use a 1.4v hearing aid battery and space it with a small #9 faucet O-ring if necessary.
In my case the battery is just for the meter, but in electro the battery will be used for the meter then it will decided the 'correct' shutter speed...I've tried what matt denton suggest which is to change the ASA setting in my lynx 5000e, I'm using 3volt battery while some manual said that 5000e needs 2.7volt battery...I tried to compare the reading from CdS meter and what I have in my dslr and in order to have both matched I had to change the ASA setting in my lynx from 200 (which is the film I use now) to 400, from there all the reading that I have in 5000e is exactly what I have in my dslr....however joe wolff added that, this is not the case of broken CdS, but because each camera manufacture has sets their own standard how the meter will read in such situation and this might or might not suit the taste of each owner (in my example, I tend to have my mg-1 and lynx 5000e have 2-3 stops over exposed compared to what I have in when I'm using with dslr, MG-1 is different but with lynx 5000e which is manual exposure camera, all setting in 5000e which is shown 'correct exposure' by CdS censor in the same condition is always 2-3 stops overexpose then what I have in my dslr)...
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monopix
Cam repairer
I think we need to clarify which cameras and exactly what we are talking about here.
Yashica produced a number of different RFs and they are not the same and use different metering systems. The camera Joe is referring to uses a silicon metering cell with no batteries and, as these cells age, their output reduces and so some adjustment of the metering may be required. Any camera that uses a cds cell and a battery shouldn't need this - though I have seen instances where the cds cell seems to become insensitive and then adjsutment may be required.
The main issue under discussion here though is whether different battery voltages effect the meters - not whether meters become insensitive with age.
The Yashica Electro series which I've checked for battery voltage tolerance are very tolerant and will work (more or less) with a wide range of batteries and battery voltages. The main effect of using a less than ideal battery is the non-working of the battery check light and rather dim exposure indicators. The metering/exposure system however will work perfectly with a wide range of voltages.
Your camera, which is obviously a different model, may well be different and may be less tolerant of battery voltage variations. If what you do works for you, that's great.
Sorry if I made any assumtions about which camera you were using.
Yashica produced a number of different RFs and they are not the same and use different metering systems. The camera Joe is referring to uses a silicon metering cell with no batteries and, as these cells age, their output reduces and so some adjustment of the metering may be required. Any camera that uses a cds cell and a battery shouldn't need this - though I have seen instances where the cds cell seems to become insensitive and then adjsutment may be required.
The main issue under discussion here though is whether different battery voltages effect the meters - not whether meters become insensitive with age.
The Yashica Electro series which I've checked for battery voltage tolerance are very tolerant and will work (more or less) with a wide range of batteries and battery voltages. The main effect of using a less than ideal battery is the non-working of the battery check light and rather dim exposure indicators. The metering/exposure system however will work perfectly with a wide range of voltages.
Your camera, which is obviously a different model, may well be different and may be less tolerant of battery voltage variations. If what you do works for you, that's great.
Sorry if I made any assumtions about which camera you were using.
pakeha
Well-known
any problem with using v625u for 1.35?easy to find and cheap, dont last as long though as they are alkaline, meter matches close enough
btgc
Veteran
AFAIK alkaline 1.5V cells come close to 1.35V during their lifecycle, just this moment isn't long enough to think about it as replacement of mercury cell. First it is above 1.3V, matches it for short time and then falls below desired value.
Otherwise people wouldn't hunt for old stock of mercury cells or use hearing aid 1.4V cells, I guess.
Otherwise people wouldn't hunt for old stock of mercury cells or use hearing aid 1.4V cells, I guess.
pakeha
Well-known
v625u are 1.35v, here and agree with the use of 1.5, so even a 1.35 alkaline not good option? cheers
eliemarga
Member
no worries mate, it's just my curiosity after all...I own both electro MG-1 and Lynx in both camera I need to change the ASA setting to get my meter read what I want, in that case I assume the metering system using CdS on yashica RF is the same, but I might be wrong
, but well...it's me anyway, and not the topic of the thread sorry for being OOT :bang::bang: