How it Works
OLYMPUS
Loading...
batt-adapt-US
Service Manual
14 pgs496.48 Kb0

OLYMPUS batt-adapt-US Service Manual

The mercury cell problem and its solutions.
page
photo (still) cameras, exposure meters and accessories that use PX13 / PX625 / MR9 cells. 9: List of cameras, exposure meters and accessories that use PX13 / PX625 / MR9 cells. 10: For the more technically challenged: a step-by-step guide for making a battery adapter with tiny S.M.D. parts. 11: Ordering information and prices (incl. shipping costs) for ready-made adapters, kits or a hardcopy of this article. 12-14: F.A.Q. frequently asked questions: please READ this first before you place your order or ask me questions.
General information about mercury cells and various solutions for replacing the banned mercury cells.
The now (for environmental reasons) banned mercury cells have caused problems for a lot of (vintage) camera and exposure meter owners who are now facing inaccurate exposures. The constant output voltage (1.35 volts) of the mercury cell was used as a reference voltage and for powering the meter and surrounding electronics. Depending on the circuits in an exposure meter a constant voltage is actually necessary or not. A Pentax Spotmatic, for instance, has a ‘bridge’ measuring network and does not need an exact 1.35 volts. This camera works perfect on a 1.55 volts alkaline or 1.6 volts silver-oxide cell. When an alkaline or silver-oxide cell is used instead of a mercury cell without an adapter or other special measures, deviations of up to 4 Light Values! (Konica TC) can occur. In general a camera or exposure meter will not be damaged when a silver-oxide or alkaline cell is used instead of a mercury cell, however, I cannot guarantee this will be the case for every camera. To check whether or not a camera or exposure meter works correctly on an alkaline cell; measure the exposure on a bright sky and in a dim lit room with a fresh alkaline cell and again with a mercury cell or compare the readings with an exposure meter or camera that exposes correctly. If the readings are the same with both cells/exposure meters in bright and dim conditions the mercury cell can be replaced with an alkaline cell without any problems. If the exposure readings in dim and/or bright conditions are more than 0.5 L.V. ‘off’ an alternative power source will be necessary once the mercury cell is depleted. For slides a variation in exposures of 0.3 L.V. can already be a problem. If the camera or exposure meter does not work properly on alkaline or silver-oxide cells there are a few options:
- Stock enough mercury cells to last a few years.
- Have the camera or exposure meter adjusted to work
correctly on silver-oxide cells.
- Modify the camera/exposure meter by soldering one
(or more) Schottky diode(s) in series with the wire from the battery compartment so it can take silver­oxide cells. (option 5, page 3)
- Use zinc-air cells, see page 2.
- Use one or more ready-made or homemade battery
adapter(s).
Author: F. de Gruijter, Waddinxveen, The Netherlands. battery.adapter@orange.nl
1
Index.
Most batteries that were available in mercury versions are currently available in silver-oxide and/or alkaline versions. Lithium cells are not suitable for use in most cameras/exposure meters that were dependant on mercury cells even when camera manufacturers advice them (see bottom page 2 and 5). Adapters are available from various suppliers but usually at high prices (around $ 30.-) beware of unusually high shipping costs that most suppliers charge. Take shipping costs into account when ordering batteries and/or adapters on the web. Check out the following sites for battery adapters: www.criscam.com and www.rolleicamera.com/sales-batt-adapt.htm and
http://www.smallbattery.company.org.uk/index.htm?http:// www.smallbattery.company.org.uk/sbc_mercury_catalog ue.htm. To replace PX32, TR164, HM-4N or (2) 640A
mercury cells go to the site from the ‘Yashica guy’:
www.yashica-guy.com/document/battery.html they sell
adapters for a nice price (around $ 15.-) and with ‘normal’ shipping costs. The ‘Yashica Guy Pro Adapter’ replaces the PX32 and equivalents that are used in the Yashica rangefinder camera series: Electro 35 G / GS / GT / GSN / GTN / MG-1. For the Lynx 5000E and Lynx 14E models there is a replacement for the 2 pieces of 640A mercury cells. There are ‘adapters’ that cost only a few dollars,
www.paulbg.com/Nikon_F_meter_batteries.htm these
metal rings are intended for physically adapting zinc-air 675-cells so they will fit in a 625-battery compartment but do not lower the voltage. These rings cannot be used with alkaline or silver-oxide cells. Expensive adapters (up to $ 35.00) adapt the common SR44/S76/357 (or 386) silver-oxide cell in size and lower the voltage to 1.35 volts. Another option is to make your own adapter. On pages 6 to 8 is a comprehensive do-it-yourself guide for making a homemade adapter like the one the right or order this adapter ready-made (see page 11). In the following pages there is more detailed information regarding mercury cells and their replacements and concerns mainly the PX625 and the PX27 (page 5).
Dimensions in this article are given in millimetres (mm). To convert millimetres to inches multiply the millimetres by 0.04 this will give a reasonable approximation. For an exact conversion:
1 Inch = 25.4 mm, 1 mil (0.001 Inch) = 0.0254 mm.
version 8.5 - July 2007
Mercury cells such as PX13, PX14, PX27, PX32, PX400,
PX625, PX640, PX675 and other types are (because of environmental reasons) no longer available, produced and imported in most countries all over the world. The mercury in the cell is a highly toxic heavy metal and can do a lot of damage to the environment. There are many manufacturers that made the 625-cell under their own part number: 4370, 4371, PX13, V13PX, EPX13, V625PX, PX625, KX625, RPX625, EPX625, HD625, PN625 RM625, 4625, 625, H1560, H-D, HS-D, M01, MR9, 1124MP, M20 and 8930. Many salesmen do not know the difference between mercury and alkaline cells and will try to sell you (in all ignorance) alkaline cells stating these cells are the same as mercury cells and are interchangeable without any problems, sadly however, this is not true! There are rumours mercury cells are still produced and available in China, look for those on the web. Make sure you are not sold ‘old stock’ that has been waiting on a shelf for 6 years or longer, these cells will certainly not last long! The main reason mercury cells were used is the constant output voltage of these cells during their lifespan. This constant output voltage makes simple and effective exposure meter circuits possible without the need of (expensive) reference components and a lot of electronics. Their large capacity and low prices also made it popular.
Zinc-air cells are intended for use in hearing aids to replace mercury cells. The cheap 675-hearing aid cells are sold in blisters and can be used in most cameras/ exposure meters directly but their lifespan is limited to only 2 to 4 months depending on make, humidity and temperature whether current is drawn or not since they literally dry-out over time. These cells are smaller than 625-cells and need to be held in place with an adapter­ring. There are cheap adapter-rings (a few dollars) made from metal but anything to centre the cell will do also, like a rubber O-ring, faucet washer or a rolled piece of paper. Some cameras, however, use the protruding rim of the PX625 cell to make contact with the battery compartment and won’t work with a ring that is not made of metal. In this case a metal ring is necessary to make contact with the battery compartment. As long as the seal remains on the battery it will have a shelf life of at least 6 years. After the seal has been removed air gets in the cell through little holes, the cell is activated and after 1 to 5 minutes the output voltage will be high enough and ready for use. This cell needs access to fresh air or it will not be able to deliver the right voltage so a hole or gap somewhere in the battery compartment or battery-cap is necessary. Zinc-air cells, however, cannot be stacked directly on top of each other since the holes from one cell (or more, if 3 or 4 cells are used) are sealed off by the negative side of the other zinc-air cell(s) and will not be able to deliver the proper voltage. The stacking problem can be solved easily with the following 2 solutions.
Stack solution 1: make an empty battery casing as described on page 10 (the right half of the page). Make 3 small dents from the outside of the plus (+) side of the battery casing so that on the inside 3 small bumps appear as shown on the right. A 675-cell that is placed inside the battery casing will now be somewhat elevated so air can get into the air-holes. Zinc-air cell(s) will fit perfectly in a battery compartment when this adapter is used because the
0.04" (1mm) height difference between the 675 cell and the PX625 cell is corrected too.
2
Stack solution 2: Use a conductive spacer between the cells with a small piece cut out of it as shown on the right. Make this from copper or other metal foil. The example on the right is made from a conductive self-adhesive foil that can
easily be applied to a zinc-air cell as shown on the left. The glue on this sticker is conductive. When this sticker is applied to a cell so that one air hole remains open the
sticker will seal off the other holes and therefore will last longer. The air can reach the cell through the gap formed by the cutout part of the sticker. When 675-cells are used to replace PX625 cells you might need to fill up the space (0.04" = 1 mm per cell) with metal no. 10 flat washer(s) (hardware store). Centre the cell with rubber O-rings or (if needed for making electrical contact) order the tightly fitting metal ring from
www.paulbg.com/Nikon_F_meter_batteries.htm.
For cameras like the Rollei 35’s these solutions are not a good option because the (half full?) film must be taken out of the camera to change the batteries.
There are ‘replacements’ for the PX625, the ‘Wein’ MRB625 and ‘Rittz’ MX625. Regrettably these cells are expensive compared to 675-hearing aid cells. These cells are 675-cell sized and come with metal adapter-rings to centre them. Both of these cells have fewer holes than ‘normal’ 675-cells and, therefore, will last longer. Unfortunately these metal rings are quite loose around the cell and not easy to apply (not so with the metal ring mentioned above). The ‘Wein’ MRB625 also has a somewhat lower output voltage (1.36 volts). It has only 2 holes instead of the usual 3 or more; this causes the cell to dry-out more slowly and will therefore last longer, up to 1 year according to the manufacturer. If you don’t mind changing and buying these expensive 625-substitutes regularly you can have a very good substitute in these cells.
Alkaline cells such as LR44 (60-80 mA/h) and 625-alkaline ‘replacements’ such as the V625U, KA625, R625, EP625G and LR9 (150-200 mA/h) are not suited for most (vintage) cameras and exposure meters. These cells are often sold (a piece or in blisters) on markets, in warehouses, dump-stores and drugstores. They cannot be used because of their too high voltage and, more important, their sloping discharge properties (see ‘dis­charge comparison’ chart on page 3). A fresh cell has a voltage of 1.55 volts, then rapidly falls to 1.45 volts and falls slowly down to 0.9 volts. Alkaline cells are inexpen­sive and only if there is no difference or if the differences in readings of the exposure meter are smaller than
0.5 L.V. in all light conditions compared to readings with the original mercury cell, these alkaline cells can be an excellent replacement.
NiCad or NiMH rechargeable cells are also not an option because of its limited capacity (60-80 mA/h), sloping discharge curve and high self-discharge rate. When fully charged they have a voltage of 1.38 volts but falls very rapidly down to a much too low 1.2 volts.
Lithium Manganese (Li-MnO2) cells are not suited as a replacement for mercury cells because of a much to high output voltage (3 volts) small capacity, sizes and their sloping discharge characteristics (see: chart on page 3 and text (right bottom) page 5). Lithium-Iron-Disulphide batteries (1.5 volts) are available in ‘AA’ penlight size only and recommended for usage in low temperatures.
Silver-oxide cells, under certain conditions, can be good alternatives. The voltage of these cells, 1.6 volts, is too high to be used directly without reducing the voltage. Silver-oxide cells, however, do have a constant output voltage like mercury cells. An adapter with a build-in device to lower the voltage to (an average of) 1.35 volts is the solution. An SR44, S76, 11077SOP, SP76, EPX76, SB-B9, RW42 or 357 silver-oxide cell (150-190 mA/h) with an adapter fits in the battery compartment of a camera/exposure meter. There are also alkaline cells with the same outline as the SR44 such as LR44, A76, 1166A, V13GA, PX76A and RW82, do not mistake these for silver-oxide cells, they are not the same and certainly not interchangeable.
An adapter has two functions.
1. Adaptation of the somewhat smaller SR44 cell to the larger and differently shaped 625-cell.
2. Lowering the output voltage of a silver-oxide cell from 1.6 volts to the desired 1.35 volts.
Below are the discharge characteristics of various equal sized batteries under identical load conditions.
3
2.5
2
1.5
1
output (volts)
0.5
0
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1
service life of equal sized cell with identical load
discharge comparison
silver-oxide
alkaline
NiMH
mercury
zinc-air
Li-MnO2
Attention! The ‘battery check’ reading on a camera or exposure meter may give erroneous readings when a battery adapter is used because the ‘load’ of the test circuit may be too high, this does not mean the adapter does not function properly. When a fresh silver-oxide cell is used with an adapter, mark or remember this ‘battery check’ reading and use it as a new ‘full battery’ reading when using an adapter.
Be sure never to short-circuit the cell and adapter, this may result into failure of the Schottky diode.
Alkaline cells cannot be used in an adapter because their output voltage is not constant enough during its lifetime. Only Silver-oxide cells can be used because they have a constant output voltage like mercury cells.
Options for replacing the PX625.
Option 1: have the camera/exposure meter adjusted to
work correctly on a (1.6 volts) silver-oxide cell. This is a sometimes costly, but probably best, long-term solution. An old camera or exposure meter is bound to be a little inaccurate after more than 10 years of service and it can’t do any harm to have it serviced anyway. The cost of servicing and or adjusting or calibration is dependant on make, model and service department that does the calibration. An adapter is not necessary in this case.
Option 2: zinc-air cells can be a good solution in some cases but only if battery compartment is accessible from the outside of the camera. Info on zinc-air is on page 2.
3
Option 3: an adapter is a good solution if the camera or exposure meter must remain in its original state or if the wires from the battery compartment are not easy to reach as with the Rollei 35 series. Also if the batteries last 1 year or more, or if the camera/exposure meter is not used very often a battery adapter is a good solution. Use the $ 15.00 ready-made adapter (see page 11) or the $ 29.99 MR9 adapter from C.R.I.S. Camera Service
www.criscam.com or the adapter from Gossen (this
adapter replaces 2 PX625 cells at once). C.R.I.S. also has adapter solutions for other types of mercury cells. For replacement of PX32, TR164 or HM-4N cells look at:
www.yashica-guy.com/document/battery.html. The MR9
adapter from C.R.I.S. has two drawbacks; the first problem is its inability to handle currents over 200 µA (microamperes) very well because of the applied diode (probably 2 germanium diodes in series). Readings with a Nikon F can be ‘off’ –1 to +3 L.V. when the C.R.I.S. MR9 adapter is used! (See page 4.) Another problem is the height of this adapter with a S76/SR44/357 silver-oxide cell in it, which is 0.015 inch (0.38 mm) thicker than the original PX625 cell and won’t fit well in some cameras/ exposure meters. The MR-9 fitted with a 386 cell has too little height and an even smaller capacity than when it is fitted with a 357 cell. An adapter with a 357 cell has half the capacity of a PX625 cell and, therefore, will last about half as long too. The diode is placed in the bottom of the MR9 adapter and not in the rim like in the homemade adapter that does not suffer from these drawbacks.
Option 4: adjust the camera/exposure meter yourself. This can be quite difficult and you can do more harm than good. There are no general guidelines on how to do this since every camera/exposure meter is different and needs another method or specific order of adjusting under controlled conditions. So do this ONLY if you know exactly what you are doing!
Option 5: solder one (or more) Schottky diode(s) in series with the wire from the battery compartment and use silver-oxide cells. A diode is a semiconductor that passes current in one direction and blocks in the other direction. Every diode has a certain voltage drop across it as current flows through it depending on the material it is made of (germanium or silicon), its structure (Schottky) and the amount of current flowing through it. (see page 4) If the ‘+’ of the battery is connected to the chassis of the camera or exposure meter, solder the diode(s) in series with the wire from the battery compartment as in the upper example on the right. If the ‘+’ of the battery (also) has a wire attached to the battery compartment you can solder the diode as shown in the lower example. The colour of the diode and ring may vary depending on make and type. The ring or coloured band on the diode represents the cathode. Make sure you have enough room to place the diode and insulate the diode and its wires properly. If the camera takes 2 cells, solder 2 Schottky-diodes in series with the wire or one (1) 1N4148 silicon-diode, 3 cells: solder one (1) 1N4148 silicon diode and 1 Schottky diode in series. 4 cells: solder two (2) 1N4148 silicon diodes in series.
Option 6: a homemade adapter can be a good solution (see option 3). A homemade adapter is cheaper and performs better than the C.R.I.S. Camera Service MR9 adapter. You do need some manual skills for the assembly of an adapter. Comprehensive descriptions for making homemade adapters are on pages 6 to 8 and 10.
Choosing your battery adapter.
.
Cameras and exposure meters that last a year or longer with their batteries, such as Rollei 35’s, have a maximum drawn current between 0 - 200 µA (micro-amperes). For all those cameras/exposure meters the C.R.I.S. MR9 adapter can be an excellent solution as long as the battery compartment allows the 0.015 inch (0.38 mm) extra height. For cameras/exposure meters with a current between 0 - 700 µA, a homemade adapter fitted with a BAT83 Schottky diode is an even better solution and is
suited for (almost) all cameras and exposure meters.
Cameras and exposure meters with a maximum current of 2 mA (1,000 µA = 1 mA) like the separate Nikon F Photomic-finder might be better of with a homemade adapter fitted with a BAT43. Compared to a BAT83, however, the difference in exposure is marginal. If the
0.015 inch (0.38 mm) extra height of the MR9 adapter with a silver-oxide cell poses a problem, the homemade adapter is the only solution since it has the exact height of the original PX625 mercury cell. Below is a comparison chart for an adapter fitted with a BAT43 and BAT83 Schottky diode, The C.R.I.S. MR9 adapter, PX625 mercury and V625U alkaline cells are also shown in the chart. All measurements are made at room temperature with a silver-oxide cell as a power source.
1.6
1.5
1.4
1.3
1.2
output (volts)
1.1
1
0.9 1 5 9 15 25 42 75 130 230 330 500 700 1000 1500
PX625 mercury
V625U alkaline
MR9 C.R.I.S.
BAT43
BAT83
output comparison
current (micro-amps)
The X-axis from the chart is neither logarithmic nor linear for the following reasons:
1. Every increase in Light Value means doubling of the light-level of the previous Light Value resulting in the following light-level scale: 1, 2, 4, 8, 16, 32, etc.
2. In most vintage cameras/exposure meters a CdS-cell (Cadmium Sulphide cell, a Light Dependant Resistor) was used as a light sensitive device. The variation in resistance is not linear to the amount of light falling on this resistor, therefore, the current through the resistor, if a constant voltage is applied, also will not be linear to the light level.
The steps on the X-axis are analogue to Light Values from (this case) a Nikon camera. (L.V.1 = 1 µA to L.V.15 = 1,500 µA). Ideally the output voltage of an adapter, under varying current loads, should be equal to the output voltage of a mercury cell. The voltage drop of a (Schottky) diode is dependant of the current through it. As the current increases the voltage across the diode also increases (a little), because the output of a silver­oxide cell remains the same under varying current loads, the output voltage of the adapter will decrease only slightly. In essence the Schottky diode acts as a 'constant voltage drop' that is (almost) current independent.
4
Research done on various voltage lowering diodes.
A multimeter with current measurement ranges was used to measure the minimum and maximum drawn current from the battery when it is connected in series with the battery and the camera/exposure meter. The current is measured in low light level conditions (indoors in a not too bright room) and in bright conditions (on a bright sky, not directly into the sun in case of an SLR!). If the maximum current remains below 700 µA the BAT81, BAT82, or BAT83 (DO-34), BAT41, 1N5711 or 1N6263 (DO-35), or BAS70J (S.M.D.) can be used. If the current range is between 15 µA and 2 mA the BAT43, BAT46 (DO-35) or BAT54J (S.M.D.) will do fine. If the current range is between 50 µA and 5 mA the BAT47 (DO-35) will do. Above 5 mA an Schottky diode is not an option anymore. Schottky diodes come in different packages, the DO-34 (Diode Outline) measures (max.) 3 mm long (without the wires) and 1.6 mm across. The DO-35 measures (max.) 4.3 mm long and 1.9 mm across. Very small S.M.D. (Surface Mount Device) Schottky diodes such as BAT54J and BAS70J also can be used. The ‘J’ suffix is very important in this case, it stands for a SOD-323 (Special Outline Diode) casing which measures only 2 x 1.5 x 1 mm (L x W x H) and has two pads for soldering it directly onto a P.C.B. (Printed Circuit Board) without the need of any wires. If little pieces of wire are soldered onto these solder pads this diode can be used also. Below is a comparison chart for various Schottky diodes, C.R.I.S. MR9 adapter, PX625 and V625U cells, 1N4148 silicon diode, AA119 germanium diode(s) and a 2 kΩ (kilo-Ohms) resistor. All measurements were made at room temperature with a silver-oxide cell.
Comparison of diodes, batteries and MR9 adapter
1.6
1.5
1.4
1.3
1.2
output (volts)
1.1
1
0.9 1 5 9 15 25 42 75 130 230 330 500 700 1000 1500
current (micro-amps)
PX625 mercury
SR44 silver cell
V625U alkaline
MR9 C.R.I.S.
2 X AA119 Ge
AA119 Ge
1N4148 Si
BAT43
BAT83
BAS70J
2k resistor
BAT47
BAT54J
Schottky diodes, other than the ones mentioned in the chart above, also have been measured but are not included since they have identical characteristics to other diodes already shown in the chart. The BAT81, BAT82 and BAT41 have similar characteristics as the BAT83. The 1N5711 and 1N6263 are positioned exactly between the BAS70J and BAT83. Do not use diodes other than the ones mentioned above. Germanium diodes (AA119 or OA types) haven’t got the right characteristics 2 germanium diodes in series will perform like a Schottky diode up to 200 µA, above this point the output voltage will be too low for the exposure meter to give accurate readings. Silicon diodes, like the common 1N914 and 1N4148, clearly have a much too high voltage drop (0.5V); as a result, the output voltage will be far too low. A resistor is, unlike a (Schottky) diode, a linear element i.e. the voltage across a resistor would vary linear related to the current flowing through it and therefore cannot be used. (see 2kΩ resistor line in the graph above)
Note: The output voltage of an adapter with a silver-oxide cell cannot be measured with a multimeter without an additional ‘load’. The internal resistance of a multimeter is very high, as a result hardly any current will flow through the diode and the voltage across the diode also will be negligible. The output voltage that is measured will be around 1.5 to 1.6 volts and not around 1.35 volts. If the adapter with a silver-oxide cell is loaded with a resistor of around 10 kΩ (kilo-Ohms) the average output voltage, when used in a camera or exposure meter, will be measured.
Temperature influence on Schottky diodes.
As with all semiconductors, Schottky diodes also react to changes in their temperature. When the temperature increases the voltage drop across the diode decreases, as a result, the output voltage of the silver-oxide cell/ diode combination will increase. When the temperature decreases the voltage drop across the diode increases, therefore, the output voltage of the silver-oxide cell/diode combination will decrease. For Schottky diodes the temp­erature influence on the voltage drop is somewhere between -1.2mV/oC to -1.6 mV/oC depending on type and current. Most cameras/exposure meters will be used at room temperature or somewhere around it. Below freezing point a lot of cameras will also have even more problems than just with their batteries. A camera with a temperature of over 104oF (40oC) feels very hot if you keep it in your hands. Mostly, cameras/exposure meters will be used within a temperature range of 32oF (0oC) to 104oF (40oC). The measured output voltage of a battery adapter fitted with a BAT83 Schottky diode at tempera­tures of 32oF (0oC), 68oF (20oC) and 104oF (40oC) is shown in the chart below.
temperature influence on BAT83 Scottky diode
1.6
1.5
1.4
1.3
output (volts)
1.2
1.1
The PX27 mercury cell and its replacement.
PX625 mercury
BAT83 @ +40oC
BAT83 @ +20oC
BAT83 @ 0oC
1
1 5 9 15 25 42 75 130 230 330 500 700 1000 1500
current (micro-amps)
Cameras and exposure meters that take PX27 mercury cells (150-180 mA/h) also will need a replacement. If PX27 mercury cells can be found keep a few of them in stock. There are plenty alternatives for replacing the PX27 batteries such as SPX27BP or PX27S silver-oxide batteries or the PX27A alkaline battery, these batteries are the best alternatives as a replacement. Also battery
adapters that take 386 cells can be used. Another alternative for this battery is a stack of 4 alkaline LR44 or 4 silver-oxide SR44 cells. Stack 4 of these cells atop of each other and wrap a thin sheet of plastic or paper around it as shown on the left. Use cello-tape to keep
the roll together, make sure the cells do not stick to this roll. The plastic roll must be somewhat loose around the cells and keeps the cells together and isolates the individual cells to prevent them from being shorted by the metallic wall of some battery compartments. This
5
stack will fit in most battery compartments (provided the battery compartment contacts allow 1.5 mm extra height). Most cameras and exposure meters will not have any problems with a voltage of 6.2 volts instead of 5.6 volts from the original PX27 mercury cell. Minox 35 and Rollei cameras for instance work perfectly on this somewhat higher voltage and do not need to have the voltage lowered to 5.6 volts. If this stack won’t fit in the battery compartment (Rollei 35TE / SE / LED), 386-silver-oxide cells can be used. A 386-cell (120-140 mA/h) is 1.2 mm shorter compared to the 357 (SR44) cell (150-190 mA/h) and if 4 of these cells are stacked they will be 3.7 mm short. Fill this gap with metal ring(s) to obtain the correct height. There are adapters on the market that use 4 of these SR43/386-cells to replace the PX27, such as the ‘Minox battery conversion kit’ for ordering these look at:
http://www.rolleicamera.com/sales-batt-adapt.htm or the
V27PX adapter from C.R.I.S. This adapter does not have a voltage lowering circuit and delivers 6.2 volts. The adapter is suited for the Rollei 35SE, 35TE, 35LED, Minox 35’s and a lot of other cameras and exposure meters. Look at page 1 for more adapter selling websites for replacing various types of mercury cells. If you still own a PX27 cell you can easily check if a stack of 4 alkaline or silver-oxide cells are the answer to the problem by measuring exposure on a bright sky and in a dim lit room with the PX27 and with 4 LR44 alkaline cells. If the readings of the camera/exposure meter are the same with both types of cells the PX27 can be replaced with a stack of 4 alkaline or 4 silver-oxide cells without any problems. Do not use alkaline and silver-oxide cells together! Stacking 4 zinc-air 675-cells is not an option because the air holes from 3 of the 4 cells will be closed off by the other cells and will not be able to deliver the necessary current.
If the readings of the exposure meter are not the same with both kinds of batteries only silver-oxide cells can be used and a 1N4148 silicon diode with a BAT83 Schottky diode must be soldered in series with the wire from the battery compartment. This will give the proper voltage drop and will bring the output voltage down to around
5.6 volts. Solder these diodes in series as shown on the right. If only the ‘-‘ side of the battery compart­ment has a wire attached to it; solder the 2 diodes in series with this wire, the cathode of the diodes (the stripe or ring) must point towards the ‘-‘ of the battery stack.
CR1/3N or DL1/3N cells Lithium-Manganese cells are NOT a good replacement for the PX27 mercury cell even when camera manufacturers recommend them. These cells have a nominal voltage of 3 volts (when fresh) and a height of 2 SR44 silver-oxide cells. These lithium cells,
however, have an extremely sloping output voltage (see ‘discharge comparison’ chart on page 3). From the moment these cells are used their voltage will drop steadily. When it is halfway its capacity the output voltage has already dropped down to 2 volts and will continue to drop further to 1.2 volts before
ending its useful life. Most cameras using these cells have electronic shutters. A Lithium cell nearing depletion may give a ‘normal’ battery test indication but cannot deliver the current bursts that are needed for proper shutter operation resulting in wrong exposures and/or ‘strange behaviour’ in some cameras.
Loading...
+ 9 hidden pages
Buy Points How it Works FAQ Contact Us Questions and Suggestions Privacy Policy Cookie Policy Terms of Use