Cyclone Analogic Bass Bot Bedienungsanleitung PDF herunterladen (Seite 6)

These cells have a self-discharge rate of less than 1% per year, depending on the temperature. With the

ordinary memory chips, which draw very small fractions of a microamp, their life would be determined

almost entirely by their low discharge rate. Only if the 32 Bank Memory system is maintained for long

periods of time at elevated temperatures would the memory chip current drain contribute significantly to the

discharge of these batteries.

With the standard memory chips, the two drives for VRAM (the supply voltage of the memory system) are

the same as those described on page 3. When the 32 Bank Memory system is installed, the second diode is

removed, so the C-cells, if any are installed, have no role in powering the memory system when the machine

is turned off. The first diode (which drives VRAM when the machine is turned on) has a second diode

added in series, to drop the VRAM drive another 0.6 volts or so. This is to cope with the situation of

running from fresh alkaline batteries (whose total voltage may reach 6.5 volts or so) which, with a single

diode voltage drop exceeded the 5.5 volt maximum supply voltage specification of the 32 Bank memory

chips. This caused them to behave erratically. The first dozen or so Devil Fishes with 32 Banks of Memory,

from July 1999 to February 2000, did not have this second diode. Please use somewhat discharged alkaline

batteries if you are running these machines from C-cell batteries.

The backup current of the 32 Bank Memory system is higher than the very low, and difficult to measure,

current of the standard memory chips. I used several types of memory chip, but since mid-2001 have been

using a large batch of very low current Samsung chips. Typical backup currents are 0.02 microamps at

18°C, to 0.40 microamps at 50°C.

The 100uF capacitor would not supply the 32 Bank Memory system chips for very long. However, the

capacitor is not important for this purpose since, until the end of 2014, we always installed a permanently

installed large-capacity cylindrical lithium battery.

In the absence of accurate knowledge of temperature, memory chip current drain and self-discharge rates, the

most accurate characterisation I can give of this solution to the memory backup problem is that the battery

will last at least ten years and probably for several decades. It would not be surprising if they are still fine in

60 years or more. With the 32 Bank Memory system, assuming it is generally at cool room temperature, say

20C, with a current of around 0.03 microamps, the theoretical life of the battery, not counting self-discharge,

would be 950,000 / 0.03 = 3,614 years.

The soldered-in nature of the battery means there are no potential problems with connections to a battery

holder. These cylindrical cells seem to be very long lasting, with no evidence of electrolyte leakage, or

excessive self-discharge.

It is possible to measure the voltage of the battery with digital volt meter applied to a test point which is

accessible if the Mode knob is removed. There is another test point there which, if shorted to ground, will

drop the VRAM supply and so erase all the data, allowing the chips to come up with their "random" states.

There have always been two problems with this arrangement, neither of which I considered worth worrying

about:

1 - If C-cell batteries were installed (which are only needed for powering the

machine, since they have no role in memory backup) and the machine was left on

accidentally for a long time, these batteries could be flattened, and leak –

corroding the battery contacts and perhaps parts of the circuitry.

2 - The soldered-in lithium battery can only be replaced by a technician completely

dismantling and reassembling the Devil Fish, which is difficult. However, there's

no reason to believe the battery would need replacing in the next few decades.

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