
7. TROUBLESHOOTING
B–63445EN/01
172
Parity error of SRAM that stores part programs.
A parity bit is prepared for writing data in memory correctly. There are
odd–number parity and even–number parity.
#6 #5 #4 #3 #2 #1 #0 #P#7
0 (Parity bit)
(Even–number
parity)
10110111
(1) Defective base printed–circuit board, or incorrect data in the memory
of base printed–circuit board
When this alarm occurs immediately after power is turned on, once
turn off power, then turn on power while pushing
RESET
and
DELETE
key
to perform memory all clear
If parity error is not released by clearing all memory, RAM or control
circuit of RAM may be faulty. Change base printed–circuit board.
CAUTION
When the base printed–circuit board is replaced, all the data
stored in memory is lost. Set data again, referring to chapter
3 ” Data input/output” .
(2) Low voltage of memory back up battery.
A battery alarm occurs if a voltage rated at 3.0 V drops to 2.5 V typical
(2.3 to 2.7 V).
When the memory back up battery voltage is lowered, BAT is
displayed at lower part of the screen.
When battery alarm is lit, replace with new lithium batteries as soon
as possible.
Refer to 2.6 battery replacing item and change the batteries.
(3) Base PCB is faulty
If the alarm turns off upon clearing all the memory, the RAM backup
circuit may be faulty. Replace the base PCB.
7.24
ALARM 910 TO 911
(RAM PARITY)
Points
Causes and Remedies