Self-Diagnosis Mode - Sony CNU-500 Maintenance Manual

2-6-4. Self-Diagnosis Mode

Activate the self-diagnosis mode following the procedure
below.
n
The self-diagnosis mode of CNU-500 is completed when
the system is terminated normally or when an error occurs.
• Turn on the power switch with the S4 and S5 switches
(on the AT-100 board panel) set to the DOWN and SET
positions, respectively.
a) ROM/RAM Check
• Release the switches when the monitor display shown in
Fig. 1 appears.
AT-100 Main check mode. (AUTO)
EPROM Check OK
OPTION FLASH Check
WRITE
ERASE
READ
RAM Check OK
OPTION EEPROM Check
SWITCH Check
S2
Trouble 1 : Figure 1 is not displayed on the monitor
screen.
Remedy : Confirm if IC45 and its peripheral block
or switches S3, S4, and S5 are not
defective.
Trouble 2 : The RAM check appears as an NG
display.
Remedy : Confirm if IC9 to IC12 are not defective.
CNU-500
MODE
S3 S4 S5
UP DOWN SET CANCEL
Fig. 1
b) Switch Check
1. Confirm that Fig. 1 is displayed on the monitor screen,
and set S2-1 to S2-8 sequentially to on (see in Fig. 2).
Next, set S2-8 to S2-1 sequentially to off and confirm
that the monitor display shown in Fig. 3 appears.
AT-100 Main check mode. (AUTO)
EPROM Check OK
OPTION FLASH Check
WRITE
ERASE
READ
RAM Check OK
OPTION EEPROM Check
SWITCH Check
S2
AT-100 Main check mode. (AUTO)
EPROM Check OK
OPTION FLASH Check
WRITE
ERASE
READ
RAM Check OK
OPTION EEPROM Check
SWITCH Check
S2 OK
S3
Trouble 3 : S2 appears as an NG display or appears
as neither an OK nor NG display.
Remedy : Confirm if S2 or its peripheral block is
not defective.
2-6. Self-Diagnosis
Fig. 2
Fig. 3
2-5