Fixed a Weston Master III

[BrianShaw]

I had a favorite Weston Master lightmeter that gave up the ghost one day. For a long time it had a broken glass (and still does) but gave wonderfully accurate exposure informaiton. But then it simply stopped working.

Knowing nothing about selenium cell or the innards of selelnium cell meters, I took the meter apart and found that the selenium cell is a rather thin metal wafer sandwiched between a copper finger ring and the baffles/bumpy glass. I always thought that the glass/baffle/selnium-cell was a sealed package.

All I did was clean the contact surfaces between the slelnium cell and the copper finger finger ring using a pencil eraser and a light touch. I didn't expect much, but after reassembly (specifically, after re-establishing the ground wire) the meter sprung to life again.

Yippeee! I don't name my equipment, but I might start refering to this meter as Lazarus.

Next task... find some thin glass or plastic and craft a new window.

 

[los]

Brian,

how did you get into the weston III? i read somewhere that you need a special tool. i've tried to open it, but am afraid of destroying it.

Los

 

[wolves3012]

I'd be curious to know this too. I have a III and a IV. On the IV you undo the screw in the middle of the exposure calculator and remove the dials, this then reveals two screws that hold the thing together. I'm assuming the III is the same, except the calculator has a smooth chromed middle that I don't see how you undo. There are two very small-headed nuts on the back, but I fear this doesn't lead far.

Fortunately my III works well and gives good readings, except that if you point it at the sun it doesn't go off-scale like the IV does. They do agree in "normal" light though, and give good exposures. I have another IV with a dud cell, for parts should I need them and a V, likewise with a dud cell. I like the IV best of all the Westons, simply because it has a calculator scale large enough to read without my reading glasses!

That special tool you refer to is probably to undo the screws holding the case-halves together. I made one for the IV by simply grinding a slot into a normal screwdriver, so it can fit over the threaded part - hard to explain but you'd see how easy it was if you saw the screws!