Spectra Combi II is good?

[mandoman7]

Strictly speaking no. While ageing drift on the cells obviously will alter results where some other parts will not interfere with the metering until they fail entirely, cells are no more sensitive to ageing than any other component. Indeed, as far as my adjustment attempts on old meters and cameras go, the mechanical needle instruments on older meters and A/D converters on digital ones usually seem to be the first part that develops a non-linear error that cannot be compensated any more, while the cells mostly still continue to be linear, with some decrease in sensitivity.

Some selenium cells are particularly prone to corrosion damage - but the Norwoods/Sekonics, Westons and Spectras we now mostly encounter as still working selenium meters are fairly immune against that, the vulnerable types mostly have vanished by now.

I have to admit that my statement was based on observation and not fact. I've played with many older meters (prior to selenium cells) and they always seemed to have lost their sensitivity after 20 years or so. I've always thought of old meters as one thing that doesn't get better with age...

[Nadar]

My Spectra has arrive. It has a 6.2v 4SR44 battery wich is PX28 equivalent. The meter's manual says that use a 6v PX28, so the battery aparently is not the correct. I used it a little bit taking readings. Do you think I can damage the meter using a 6,2v battery instead a 6v?

[Sevo]

My Spectra has arrive. It has a 6.2v 4SR44 battery wich is PX28 equivalent. The meter's manual says that use a 6v PX28, so the battery aparently is not the correct. I used it a little bit taking readings. Do you think I can damage the meter using a 6,2v battery instead a 6v?

The original PX28 is defined to be a 6.2V silver oxide battery (a stack of four 1.55V button cells) - nominally 6V as that is the next full number. According to the manual (which explicitly mentions Silver Oxides), this is the recommended battery type! The manual does not warn against using the alkaline PX28A of nominally 6V (rapidly dropping), even though these will probably already have been about. If you are lucky the meter is equipped to deal with the latter - if so, it can take any PX28 variant! If it does not, alkalines would be pointless, as their voltage (and hence the meters readings) may be all over the place depending on their use history.

There also are modern, lithium based replacements called a PX28L that deliver true 6V - these are far more constant than alkalines, but still have a considerable voltage drop towards the end of their life. You can safely try using PX28L, they will do no damage. Just bear in mind that a unstabilized meter using a PX28L will be off (compared to silver oxides) by a constant value (usually less than one stop, but you'll have to figure that out while you still have something to compare to!) for about half the battery capacity (i.e. weeks or months of use), and will get increasingly unreliable (alkaline like) after that point.

On the positive side, lithium cells have a shelf life of five to ten years and generally will not leak even when dead - wherever the cameras/meters can deal with them, I do prefer them to the rather leaky silver oxide and alkaline cells for that reason.