Sony RM-450 - Operational Checks and Troubleshooting; Performing Operational Checks

RM-450/RM-450CE
4. OPERATIONAL CHECK AND FAULT IDENTIFICATION
1. General
No electrical adjustment is required in this machine.
“Use of a simple checker and a built-in test program
can check al! operations.
A test program activating method and checking items
are described below,
1-1. Keyboard check
Turn On the POWER switch while pressing the
and keys at the same time,
Checking items :
LED ON/OFF
Non-locking switch operation
Locking switch operation
JOG/SHUTTLE operation of Search Dial
RS-232C line operation of KSW-1 -board
Backup data (LEARN data) verification _
ROM and RAM check by CPU on KSW-1 board
1-2. Backup function check in keyboard
Turn ON. the POWER switch while pressing the
and keys at the same time,
Checking items:
Backup function check by CPU on KSW-1 board
The “Error” is displayed when the POWER switch
is turned ON at the first time (or when the backup
capacitor C305 on the KSW-1 board is discharging).
Further error display is not made if the backup
function is normal.
The capacitor can afford to provide backup for at
least seven days.
1-3. CPU board check
Turn ON the POWER switch while pressing the
and keys at the same time.
The CPU board is automatically checked. (Start by
EJECT key on the RECORDER side.)
If a fault the operation is stopped
immediately and the error code is displayed.
is found,
For this purpose, the service tools are required,
4-1 (E)
1-4. Software operation check and REF. VIDEO
circuit check
Turn ON the POWER switch.
D219 (CHECK3 LED) on the CPU board blinks by
the software, In addition, D217 (CHECK1 LED) blinks
when a signal is entered into the REF, VIDEO IN
terminal,
1-5. Address bus check
Power ON after S201 OFF
Turn OFF the 8-bit DIP switch S201 on the CPU board
through it is usually set to ON position. The CPU
then executes NOP (00) since the data bus on the
CPU board is isolated from devices other than CPU
and pulled down by a resistor. At this time, the
address line shows simple increments, (However, a
refreshed address is assigned to A7 to Al5,) .
Observation of a waveform on the address line with
an oscilloscope makes fault identification easier.
2. Service Tools (necessary for CPU board
check)
Ref, Name Part Code Q'ty Usage
No.
J-l 9P short J-621-022-0A 2. CPU-3 board
connector operation check
J-2 PLAYER, J-621-020-OA 1 CPU-3 board
33P short operation check
connector
J-3 RECORDER,, J-621-021-0A 1 CPU-3 board
33P short operation check
J-4 8-bit DIP 1-570-623-11 1 CPU-3 board
switch operation check
J-5 VIDEO signal or sync. 1 CPU-3 board
signal generator operation check
Note: J-1 to J-4 are contained in the RM-450 service
kit (J-621-019-0A).