[rollei_list] Re: OT: Replacing Mercury Cells in a Nikon F
- From: Marc James Small <marcsmall@xxxxxxxxxxx>
- To: rollei_list@xxxxxxxxxxxxx
- Date: Sat, 03 May 2008 22:30:39 -0400
At 09:20 PM 5/3/2008, Richard Knoppow wrote:
>
> The mercury cells in my Nikon F finder finally died and
>I can get no more. I tried an experiment which works and may
>be of interest to others since it may work on other devices
>which use type 625A cells.
> The voltage of size 675 zink-air hearing aid betteries
>is correct, very nearly the same as the mercury cells.
Gosh. We have hammered this out on other Lists
but it might be new to the Rollei List. Well,
no, as Bob Shell was outspoken on it, as he had a
fiscal interest in one of the solutions, but he
simply kept chanting to buy the Wein Cell, which
is as Richard has sugested, a hearing-aid battery with an adaptor.
Most, if not all, German gear requiring PX 625 or
other mercury cells also have "bridge circuits"
(voltage regulators) which allow the use of ANY
cell. The Japanese relied on the absolute
predictability of the death-cycle of a mercury
and so left these bridge circuits out of their cameras.
Hmm. What to do? Several thougths:
-- use PX 625A's and so be it. Bob Shell hated
this suggestion as he insisted that it
compromised his demand for 1/3 of a stop
accuracy on chromes, a standard I find absurd,
and as we discussed back in the Longago.
-- use silver cells with an adaptor. I have so
rigged the Kiev light-metered VF I use on my
Hasselblad 2000 FC/M. Silver oxide cells
LAST: mine are a decade old, but, and, yes, I
just checked, are still alive and accurate.
-- Buy old stock. Richard, you did not ask, but
I cleaned out the Calgary (CA) supplies a decade
back, and I have kept mine refrigerated but not
frozen. I have a VERY few left but I would have
shared one with you, in respect for your great contributios to this List.
-- Buy off eBay. These cells are still being
manufactured in Eastern Europe and the
Orient. Some of these cells are crap and some are quite nice.
It takes about 1/10th the mercury to make a PX
625 as that which goes into a "Compact Fluorescent Light". Go figure.
Me? I use silver-oxide cells and my slides come out just fine.
Marc
msmall@xxxxxxxxxxxx
Cha robh bàs fir gun ghràs fir!
---
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