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10.3.2
Two Button Reset
The main RAM content is always restored from the EEPROM at switch on, so that in many
cases it may be possible to recover from problems by simply switching off and switching
on again. If this fails to correct the problem, bad data may have been written to the
EEPROM. In this case a two button reset may be carried out by holding the RAISE button
pressed, whilst pressing and releasing the internal RED button S1 on the main PCB. This
partially resets the RAM content and will always restore a
"He"
or
"N2"
message and a
normal display if no other faults are present.
10.3.3
Three Button Reset
If the EEPROM content is completely corrupted, of if a new EEPROM has been fitted it
will be necessary to carry out a three button reset. This completely initialises the entire
memory, setting default values for all variables and wiping out any previous
configuration and calibration data. It is carried out by holding both RAISE and LOWER
pressed whilst pressing and releasing S1 on the main PCB.
Provided a STORE operation is not performed, the EEPROM will not be re-written by
either a two or three button reset so these resets can be used as safe diagnostics
. (N.B.
This is not the case with ITC4 or some other OI instruments.)
If a reset cures the
problem, STORE may then be used in the normal way to write the new RAM content to
EEPROM.
