Yamaha RX-Z1 Service Manual page 18

RX-Z1/DSP-AZ1
The history of the protection function and the version (1
alphabet) appear in the upper section and the checksums
(4 figures and alphabets) of the main microprocessor and
sub-microprocessor appear in the lower section, followed
by the DIAG menu (sub-menu of ANALOG BYPASS of
No.1 YSS938 THR) after a few seconds.
When there is no history of protection function:
Checksum:
They are expressed in 4 figures of hexadecimal data with
2M bits of the code of the entire program added for every
octet. (0xff is added for the area where no code is
recorded or area other than ROM code.)
When there is a history of protection function:
Cause: An excessive current flowed through the power
amplifier.
Supplementary information: As current of the power
transistor is detected, the abnormal channel can be
identified by checking the current detect transistor.
Turning on the power without correcting the abnormality
will cause the protection function to work immediately and
the power supply will instantly be shut off.
17
Opening message
When there is no history Versions of main microprocessor /
of protection function sub microprocessor
NO PROTECT X/X
SUM:XXXX/XXXX
Checksums of main microprocessor / sub microprocessor
When there is a history of protection
function due to excess current
I PROTECT
SUM:XXXX/XXXX
Checksums of main microprocessor / sub microprocessor
DIAG menu display
After a few seconds
1. YSS938 THR
ANALOG BYPS
Versions of main microprocessor /
sub microprocessor
X/X