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Originally Posted by Theseus
"...give you near zero value..." ??? 
It's a little hard to understand how an ideomotor-driven device can have any value at all, zero or not.
Hopefully, J_Player understands what you are referring to, and it will be beneficial information for him. |
Hi Theseus,
I understand what Mike(Mont) is saying. The rep from the factory warned in an email not to use the setscrew on bottom except as a last resort. He said if I turn it more than a hair at a time, I may lose my place and not be able to restore the setting that I had originally. This is part of the reason why I expect it will take some time to make an adjustment. Before making any adjustments on this setscrew, I will first need to try several different "gold frequency" calculator values while trying all the settings I can make on the top dial. Then if that doesn't work, I can make some very tiny adjustments on the bottom setscrew and repeat the adjustments with the top dial and different "gold calculator values".
The rain here has stopped. I expect I will be able to make these adjustments outdoors in a couple of days when the mud dries. While I have been waiting, I did open the calculator to see the back where the batteries are changed. It is definitely not the same as my Casio fx-300ES. The circuit board is different, and it has a 2-cell supply that supplies 3 VDC to the processor, where my Casio has only one cell and a solar panel that supply 1.5 VDC to the processor. Just looking at the backs of these two calculators, I can see there are a few extra components on my Casio which probably have to do with the lower voltage supply. My Casio also has more conductors running toward the display than the one sent with the Examiner. The Casio can display up to 15 digits in the top line, while the other only displays 12. I am thinking the two calculators probably don't use the same processor, but they both seem to provide the same functions at the display while showing fewer of the digits.
What does it all mean?
To start with, different processors use different routines to drive dedicated displays that are different sizes. This means the pulse train that occurs in each of these calculators will not be the same, even though the numbers displayed have the same mathematical value. If we consider the Examiner uses the signals that are derived from the pulse trains inside the calculator, then there are two significant differences:
1. The pulse trains are different. Thus, any signal that is inductively coupled to the Examiner will be small a small pulse that can be detected inductively when a calculator clock edge rises or falls. The Casio cannot have the same pulse train regardless what number or function is entered, because part of it's routine is to drive three more digits than the other calculator.
2. The Casio is running at 1/2 the voltage as the other calculator. This means any Casio clock edges have less voltage to send out a signal that can be inductively detected. Picking up an induced signal from clock edges depends on the rise or fall time of the pulses inside the calculator, as well as the amount of current, (which is driven by the voltage). In essence, you pick up induced clock noise strongest when there is a fast movement of current through a conductor that momentarily moves to discharge a from a stored location. And this generally happens strongest and fastest when the voltage is higher. If this is the usual Cmos technology used in low-voltage calculators, the two-cell calculator will have significantly faster clock edges which should produce clock noise that can be detected inductively at a farther distance.