Yashica 5000E

[chuck_foreman1]

The Yashica Lynx 5000E among other models of similar vintage uses the PX640 /MR52 battery. This is physically the

equivalent of a double PX625/MR9 in series. Since the camera takes two of these this is still 1,4V. As we all know the

problems with Mercury batteries and this seems to require 4 x the MR9 adapter cost or 2 x the cost of a serious MR52

adapter. I am curious to hear of any reality cases using the cheaper 1,5 Alkaline solutions. There are many jury rigs. I

used 2 x modern 1,5A 625 and a short bolt to make up the difference. The lights came on, but this was not very reliable.

As I said I was hoping someone has gone this route with the modern 2x640 1,5 and can say with any certainly how far

off were the exposures . Or is this again trial and error.. ?

[allen_gara]

<p>Mercury batteries were used because their voltage doesn't drift much as the cells deplete. Older CdS meter designs were basic balanced bridges, so they depended on a steady voltage source. As such, alkalines won't work very well. Their voltage drifts as the battery depletes, and so will the calibration. Zinc air and Silver Oxide are stable, and work much better. I cut 6mm high discs of 1/2" OD aluminum rod, then cut a piece of 1/2" ID plastic tubing to keep everything vertical. One disc and a 303/357 SiOx (1.55V) or 675 zinc air cell (1.4V) = one 640. Two discs and two batteries makes two 640's. I prefer to adjust the calibration and use the 357's because they last a really long time. The zinc air probably won't require as much calibration. None of the cameras I've used these with was accurate to begin with, so how much it needed adjusting seemed more dependent on the camera condition. </p><div></div>

[donald_miller5]

You mentioned there many jury rigs. Could someone share what they tried, how well they and how inconvenient they are. I am developing

a very low tolerance for trying to find substitute battery configurations that do not work even though theoretically should. I am thinking of

something similar to what I did with digital cameras for when then batteries had relatively short life. Maybe construct a small external

battery back that accommodates aaa,aa ,c or d cells that you could wear on belt etc or attach with velcro that could plug in or connect to

dead battery something shape to fit in battery compartment on a lathe through battery cover Does this sound too impracticable? The

problem my employer just closed his doors and I have nothing to do all day but come up with ideas and projects that createt more

problems than they solve or just sit home and watch TV.

[rogerwb]

<p>Buy the Wein cells once only. The batteries can be manually pressed out and replaced with zinc-air hearing aid batteries</p>

[Mike Gammill]

<p>Yeah, the metal ring for the Wein cells will fit over less expensive zinc air (hearing aid batteries) For my Minolta SRT's and Rollei 35 and 35S I can center the zinc air cell without the ring and if I'm careful I can tighten the battery cover and it works. My Konica Auto S2 and S1.6, Olympus 35RC, and Canonet GIII 17 have to have the metal ring though.</p>

[chuck_foreman1]

Allan .. thansk for the pictures.. you had all this available. Looks like a reliable fix. AS you have spaced with aluminum

rod I'm surprised it carries current? Enough Alloy ? Anay way part of my inquiry with 640s is of course the amperage. Is

this really just a question of how long? Applications that called for 2 x PX640 (4x MR9 ) needed a higher amperage, will

they work at 1/2 amperage? Donald... Thanks for putting some thought to this.. Sitting around is often conducive to

thought and solutions...reality and practicality need due diligence too. Hope something turns up your way. Roger and

Mike. I have yet to buy a single MR9 /Wein cell solution.... too cheap and too lazy. I have thought.. "I can use these with

out a meter" as I know you have too. The Wein cell is recyclable? Didn't know that! The other solution I have

considered is much as you described a "shell" for smaller cells with step down volts etc. Thank you all for you input!

[allen_gara]

<p>6061 Aluminum has ~40% the conductivity of copper, so the resistance of a 1/2" diameter is pretty nil. In a 5000e, or other mechanical shutter cameras, it's only powering the meter, and the current draw is really tiny even if you have hi/low exposure LEDs.You could use a 1/2" brass rod, but the cost is a lot higher. I'm sure a 357 SiOx battery won't last nearly as long as the original did, but they only cost a couple bucks, and most any drugstore carries them, as well as 675 Zinc air hearing aid batteries. <br>

I think the Wein cell route is a perfectly good one too, especially if you do the air cell swap like the previous posters suggest.<br>

<br />PX640 batteries are 1.35V, and so are MR9's. Not sure I understand the 1/2 amperage question (and I think you mean 1/2 voltage).</p>

[Julio Fernandez]

<p>A somewhat contrary opinion: <br>

It is true that alkalines have a discharge curve in which their voltage drops, while mercury batteries (and silver) are much more constant in voltage during the discharge. But it is also true that most of the 60's RF cameras have a very low discharge rate (currents taken are on the order of 100 microamperes). Therefore, during normal use the battery does not really go down on the curve for a really long time. The battery stays in the initial part of the discharge curve. You are looking more at shelf life than at a discharge curve, as opposed to what you would see in a hearing aid device for instance. <br>

Of course you would need to use a different ISO setting with an alkaline; you can find the right value by comparing to a trusted photometer. But after you find the ISO, the device is linear, so it should work very well. <br>

A typical classic camera user is probably safe if the alkaline is changed once a year. I can attest that this is true for the Olympus 35SP which I have used for many years with alkalines.<br>

You can also use silver batteries. I do not like Zn-air types because they age too soon. </p>

[Mike Gammill]

<p>Another factor with zinc-air batteries is how much air can reach the cell. Exposure to air allows the cells to age faster. I get about 3 months on a zinc air in any of my Minolta SRT or Olympus OM-1. About the same with my Konica Auto S, S2, S1.6 and Olympus 35 RC. My Rollei 35 and 35S, with battery compartments deep inside camera, get nearly a year from zinc air. <br>

I don't use the alkalines much, but the SRT's seem to handle them better.</p>