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Selenium Replacement - Westen Master light meter

Eva Napp , Nov 12, 2009; 08:27 p.m.

Hey everyone!
I got a cheap Weston Master V light meter from ebay which actually said "in perfect working condition" which seems to be a false statement. The needle is not responding to light at all and I'm not sure if it is because of a dead selenium cell or if I'm doing something wrong.

My question is, is it possible to change the selenium cell myself? I saw that there is a company in London (Megatron) that actually sells the cells. Replacement by them would cost 42 pounds which just doesn't make too much sense since the Weston was supposed to become my small backup light meter. But I'm wondering if it's possible to just buy the cells and replace them myself. Unfortunately I couldn't find any manuals on that online (only a few for how to replace them in old cameras).
Any ideas? Thanks!


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John Shriver , Nov 12, 2009; 08:46 p.m.

Ask Quality Light Metric in Los Angeles. (323) 467-2265. I'm sure that they have a standard price for this, and it's probably less than 42 pounds.
They maintain light meters for the cinematographers of Hollywood.

Michael Howard , Nov 12, 2009; 09:34 p.m.

I had a Master V done my them about 6 months ago, $80, good as new. Just replacing the cell is usually not enough, QLM also replaces some of the other components. They are fantastic. Call for a quote, he will have you send it in. When he's done, he'll call and get your CC number to charge it to, and send it right out. I can't tell you enough, the guy is top notch.

John A , Nov 12, 2009; 10:37 p.m.

Yours may be gone, but I had an old one that was stored in a dark bag for several years. I took it out and it didn't work. I left it in light for a few days and it seemed to revive itself. You might try it before you send it off.

Jim Momary , Nov 12, 2009; 10:46 p.m.

Selenium cells were vapor deposited as an amorphous layer of material. Sometimes they crystallize. If the cell looks silvery it's shot, if it's still 'black--blue' it's likely ok. Now, resting the cell in light may in fact regenerate it a bit, as selenium is a photovoltaic - photoconductive - photoreceptive material. Possibly other electronic issues may also be present. DIY would involve not only replacing but probably calibrating.

I'm the manager at facility that makes selenium copier drums, so we've had a bit of experience. 30 years now, yikes! But we don't make cells alas.

Rick van Nooij , Nov 13, 2009; 02:06 a.m.

Getting a single custom-cut slabs of Selenium is a very pricey endeavour indeed.
It might be something has shaken loose during transit, if the seller said the meter was working (as doubtful as this may be). As it's not working now, you might as well open it up and see what is wrong (if you can't send it back for a refund).
It is a very simple single circuit. The selenium-cell, a resistor and the coil-needle unit.

Alternatively you could replace the dead selenium-cell with a solar-cell. And replace the resistor with a variable one. I did something similar a year or so ago with a metraphod II meter. Hardest part for me was finding a solar-cell small enough. That's a less likely problem with your weston meter. I'll go and find the online topic that inspired me if you like.

Subbarayan Prasanna , Nov 13, 2009; 02:18 a.m.

It may work out less expensive for you to buy a Leningrad 7 exposure meter. It has two scales similar to the Weston, for bright light and low light conditions, respectively. I bought one recently from EBay for less than $15 including postage. Works fine. sp.

John Layton , Nov 13, 2009; 06:25 a.m.

Please take no offense... but you did use the words "if I'm doing something wrong," implying that you may lack familiarity with these meters. In which case...did you remember to push the little needle-lock button on the side of the meter? Also, if the meter was somehow exposed to a large and sudden shock in transit, the moving plate behind the needle (which changes scales for high light vs. low light ranges) may now be resting against the needle, preventing it from moving. Hope this helps.

Eva Napp , Nov 13, 2009; 04:47 p.m.

Thanks everyone for the input! John, I have only used digital light meters before and was a bit confused about how to use the Weston although I did go over the manual. That's why I wasn't sure if I had missed anything.:-)
Well, the seller did offer me a refund but since I only paid 9 Pounds for it to begin with I guess I will just keep it and get it replaced and checked through at some later date.
Rick, if you do find the article I would be happy to read up on that as well!

Chuck Foreman , Nov 13, 2009; 06:37 p.m.

If the seller offered a refund I'd take him up on it! I suspect that it got a sharp shock and is out of whack, but again this is something for experienced repairman. On one hand it is a simple device, on the other, without having a proper calibtration (whatever that is.. a measurement against a standard I assume) how can you be assured it's working properly. Since you are in England and this is a Model V, and you do want a battery-less working meter.. you might contact the folks at Megatron. I'd personally be interested if they really can and will calibrate and restore a Weston Meter. I live in Germany and have also considered the cost...about the same as 80,00US$, I'd also have the cost of sending it to England and back!! So you have this advantage. They are plentiful enough and I think you can probably find a working exemplar... for under 20,00 pounds and test it against your digital meter for accuracy. Megatron had a calibration only price too... was it cheaper? I have seen this Megatron page unchanged for 5 years now!!

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