Selenium cell revived....
Sept 18, 2021 12:57:03 GMT
on Sept 18, 2021 12:57:03 GMT
Posted: Sept 18, 2021 12:57:03 GMT
Hi folks.
Many of you may have heard the story that dead selenium cells could be revived by simply leaving them exposed to sunlight for an extended period. I thought it was unlikely - once the cell is dead, that's an end to it - but I still do this. Well, it seems that reports of some meters' deaths may have been premature...
I recently bought a Mimy which was in lovely condition with clear glass, a snappy shutter and excellent cosmetic appearance but it's meter was unresponsive. I knew this when I bought it but decided that it was sensible to have a spare body and lens. Being an auto-exposure camera, it's of less use if the meter doesn't register although you can use flash; I've not been able to determine what the default shutter speed is when the meter's inoperative so calculating the correct f-stop is impossible. After checking the dead meter regularly, I was satisfied that there was no glimmer of hope that the selenium cell would spark back into life.
I left the camera on a windowsill facing the light and forgot about it for 10 days... I picked it up again this morning after doing the same thing on Monday for a light-meter that was bundled with some kit and was also 'dead'. You're already ahead of me - yes, both meters had resumed working. I now have three Mimy's that are working perfectly - plus an extra light-meter.
I can only assume that despite not initially being able to create a current strong enough to move a needle, there must have been enough residual cell material left to allow revival of a major part of the light-meter. It stands to reason that if the wiring in the camera connecting the cell to the auto-exposure system had failed, nothing would have resulted. However, in this case prolonged exposure to UV light appears to have revived both meters.
So, if you have an old selenium-powered meter that appears dead, there may be a possibility that all may not be lost. Well, it might not work every time but it's worth a try before consigning the meter to its new status as a paperweight...
Many of you may have heard the story that dead selenium cells could be revived by simply leaving them exposed to sunlight for an extended period. I thought it was unlikely - once the cell is dead, that's an end to it - but I still do this. Well, it seems that reports of some meters' deaths may have been premature...
I recently bought a Mimy which was in lovely condition with clear glass, a snappy shutter and excellent cosmetic appearance but it's meter was unresponsive. I knew this when I bought it but decided that it was sensible to have a spare body and lens. Being an auto-exposure camera, it's of less use if the meter doesn't register although you can use flash; I've not been able to determine what the default shutter speed is when the meter's inoperative so calculating the correct f-stop is impossible. After checking the dead meter regularly, I was satisfied that there was no glimmer of hope that the selenium cell would spark back into life.
I left the camera on a windowsill facing the light and forgot about it for 10 days... I picked it up again this morning after doing the same thing on Monday for a light-meter that was bundled with some kit and was also 'dead'. You're already ahead of me - yes, both meters had resumed working. I now have three Mimy's that are working perfectly - plus an extra light-meter.
I can only assume that despite not initially being able to create a current strong enough to move a needle, there must have been enough residual cell material left to allow revival of a major part of the light-meter. It stands to reason that if the wiring in the camera connecting the cell to the auto-exposure system had failed, nothing would have resulted. However, in this case prolonged exposure to UV light appears to have revived both meters.
So, if you have an old selenium-powered meter that appears dead, there may be a possibility that all may not be lost. Well, it might not work every time but it's worth a try before consigning the meter to its new status as a paperweight...
