Trouble Diagnosis - Yamaha 01x Service Manual

O1X

TROUBLE DIAGNOSIS

The trouble diagnosis is a function that enables to guess the
trouble point when the unit does not appear to work even with
the power turned on. For example, even when nothing appears
on the LCD and even the TEST program cannot be accessed,
the trouble point can be diagnosed by using this function. Once
the TEST program is at work, it is possible to execute the major
device operation check. Therefore, the trouble diagnosis method
used until the TEST program starts to operate is described here.
Trouble diagnosis method
Proper operation of the CPU is checked by outputting the
operation condition of the CPU to LD101 (Port D (Bit5) of CPU)
and monitoring it.
Summarized in the table below are these conditions.
CPU condition
Power ON
Power-ON resetting in process
Power-ON resetting cancelled
(program started)
SDRAM initialized
Program executed on SDRAM
CPU function initialized
Task start (interruption cancelled)
LD101 condition Trouble diagnosis
ON The reset stare continues or FLASHROM cannot be accessed at all. A hang due to an operation error after initialization
of CPU. As a major possible cause, the reset IC (IC102), buffer (IC112) of the reset signal or CPU (IC101) may have
failed.
OFF Malfunction of FLASH ROM/SDRAM
Flashing The program is not hang but operates properly. It is possible to check the trouble by using the TEST program.
100
Port D (bit 5) condition
Indefinite
"H" level by built-in pull-up resistor
"L" level by initialization
"H" level
"H/L" repeated at 500msec intervals
Bottom view
CPU
(IC101)
LD101 condition Time elapsed (msec)
Indefinite
Flashing
If the illustration of a camera is clicked, an animation will flow.
The sound is not contained in the animation.
LD101
DM
ON
OFF 0
3
250
ON 250
2000
MLN2