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ABOUT THE SELF-DIAGNOSTIC FUNCTION
This model has a self-diagnostic function. When set to the self-diagnostic mode, the quality can be assessed when the
diagnostic procedures in the chart below are followed.
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1
MAIN
| RAM (IC4), ROM (IC3) check
1. Connect the CHECKING DEVICE (refer to page I-12) to
CN7
on the MAIN
PCB,
and turn on the CHECKING
DEVICE switch.
2. Turn on the power switch.
When. the power switch is turned on, the LED of the CHECKING DEVICE flashes on and off. The first
4 flashes are for the RAM check, and the latter 4 flashes are for the ROM check. The flash number
corresponds to the RAM number and ROM number; since one RAM and one ROM
are used in this
model, flash 1 of the first 4 flashes corresponds to the RAM (IC4) check, and flash 1 of the second 4
flashes corresponds to the ROM (IC3) check. If the part is defective, the flash time for that part be-
comes longer.
RAM
ROM
2
3
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@
Examples
| |
2
1. RAM OK, ROM OK
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| 2. RAM OK, ROM defective
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8
3. RAM defective, ROM OK
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---@
-
Note: == indicates long flash time.
RAM (IC4)
ROM (IC3)
Gate array (IC2) check
While
pressing
two
C keys simultaneously,
turn
on the
power switch.
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Ml MA
Monitor pins 46~48 (DL6~DL4) of IC2 on an oscilloscope,
and check whether incremental data (see figure) is output.
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dena:
OV
3
CP
Gate array (IC1) check
1. Connect the CHECKING
DEVICE
to CN7
on the MAIN
PCB. (The Checking Device switch should be off.)
2. While pressing two D neve simultaneously, turn on the
power switch.
URAL
As
D keys
When the power switch is turned on, the LED of the CHECKING DEVICE flashes. The LED flashes 4
times, the first flash corresponding to the IC1 check. If IC1 is defective, the first flash will be longer.
. IC1 OK
—____
2. IC1 defective
>
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Gate Array (1C1)
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