HI all !
I just finished rebuilding a beautiful Ranger 9 I got off EBay. The needle was moving but did not zero out; this is a typical failure mode of the 50+ year old CdS cell.
So I decided to take it apart and replace the CdS, as well of the need for Mercury or Silver Oxide batteries. The reason you needed those to begin with, is because the Voltage needs to be constant during the lifetime of the battery. Since there was some space inside the meter, I decided to add a tiny Voltage Regulator so I could use easily available CR1632, stack them for 6V, and give the regulator plenty of room to regulate the exact 2.7V needed to drive this circuit. This means that the V will be precisely 2.7V until the two batteries are almost completely drained.
The complete reconstruction guide can be found below. Note that you will need to 3D print some parts and you can do this almost anywhere nowadays, like your public Library etc. I used PETG but you can probably do this with PLA if you make sure not to subject the meter to a high temperatures (above 50C), which you shouldn't be doing anyway ! Don't leave your equipment in your car on a hot summer day for example.
Anyway, here's the guide. Enjoy !!
And pls. let me know your stories and comments if you're able to bring your Ranger 9 back to life!!
--
Alex
I just finished rebuilding a beautiful Ranger 9 I got off EBay. The needle was moving but did not zero out; this is a typical failure mode of the 50+ year old CdS cell.
So I decided to take it apart and replace the CdS, as well of the need for Mercury or Silver Oxide batteries. The reason you needed those to begin with, is because the Voltage needs to be constant during the lifetime of the battery. Since there was some space inside the meter, I decided to add a tiny Voltage Regulator so I could use easily available CR1632, stack them for 6V, and give the regulator plenty of room to regulate the exact 2.7V needed to drive this circuit. This means that the V will be precisely 2.7V until the two batteries are almost completely drained.
The complete reconstruction guide can be found below. Note that you will need to 3D print some parts and you can do this almost anywhere nowadays, like your public Library etc. I used PETG but you can probably do this with PLA if you make sure not to subject the meter to a high temperatures (above 50C), which you shouldn't be doing anyway ! Don't leave your equipment in your car on a hot summer day for example.
Anyway, here's the guide. Enjoy !!
Weston Ranger 9 Lightmeter CdS Cell and Battery Replacement
The Weston Ranger 9 Lightmeter is a classic in photography and one of the meters favoured by Ansel Adams. This meter was a major departure from...
And pls. let me know your stories and comments if you're able to bring your Ranger 9 back to life!!
--
Alex
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