Leicameter 2 Repair with Silicon Photo Cell

As I mentioned in an earlier post, the used 1960 Leicameter 2 light meter that I purchased on eBay required a new selenium cell. There were no selenium cells to be found online. The only source, located in the UK was out of business. I read online about an alternative to selenium by using silicon based cells. These are the same cells used in calculators.The existing selenium cell is 25mm by 10mm. I was able to find a silicon cell measuring 22mm by 7mm.
Old Selenium Cell from the Front

Rear of Selenium Cell (notice crack)

I was able to find a silicon cell measuring 22mm by 7mm.

New Silicon Solar Cell

The other item needed is a resistor. Not knowing what the output of the original selenium cell is, I purchased a 100K OHM adjustable resistor.
New 100K OHM Adjustable Resistor

I soldered wires onto the new silicon solar cell. Next, on the + side I soldered inline the resistor. To take full advantage of the adjustability of the resistor, you must connect between terminal 1 and 2 (middle).

Now it is time to run some tests. I touched the terminals connected to the electromagnet with the wires from the new solar cell and voila the needle moved. I adjusted the resistor until the needle matched the reading of another lightmeter that I own. I proceeded to remove the old cell and resistor and replaced with the new solar cell. To take up some extra space I used a small piece of painted balsa wood. After reassembling I checked against my other meter and adjusted the ASA/ISO gauge to match.
Completed Leicameter 2

How it Looks on the Camera

For more information on the Leicameter click here.