Cadex C4000 SERIES, User Manual

Page: 117 / 152

Diagnostics
Introduction
The C4000 performs a number of diagnostic checks on
power-up and during service. A system failure is
detected and displayed on the LCD.
1. RAM/Clock/LCD Check
On power-up, the internal and external RAM, clock and
LCD are checked.
If the internal RAM or the LCD fails, all READY and
FAIL LEOs flash; the display is inactive.
If the external RAM check fails, the LEOs flash and the
LCD reads:
Note On RAM failure, no batteries can be serviced.
As the next step, the real-time clock chip is checked (for
units with Option-P).
If in error, the LCD reads:
::'L(:r'U!:'$YSTEM:::eRBOltttt?-::<':
L,iREALfnMEtclioCI(::sdioR;::piiSS!!,AN¥:::KEYii:,
Note Clock and print functions are inoperative;
batteries can be serviced.
Reason
Bad clock chip.
As the next step, the real non-volatile RAM is checked.
If in error, the LCD reads:
Note Data Retention has failed; batteries can be
serviced.
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