Yamaha YMC-700 Service Manual page 27

QQ
3 7 63 1515 0
When there is a history of protection function due to excess current
Cause: An excessive current flowed through the power amplifier.
Supplementary information: As current of the power amplifier 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.
Note)
• Applying the power to this unit without correcting the abnormality can be dangerous and cause additional
circuit damage. To avoid this, if "PRI" and "PRD" protection function has been activated 3 times continuously,
the power will not turn on even when the "STANDBY/ON" key is pressed. In order to turn on the power again,
disconnect the power cable of this unit from the AC outlet once and then reconnect it again.
• The output transistors in each amplifier channel should be checked for damage before applying power to
this unit.
• Amplifier current should be monitored by measuring DC voltage across the emitter resistors for each
channel.
TE
L 13942296513
When there is a history of protection function due to abnormal DC output
Cause: DC output of the power amplifier is abnormal.
Supplementary information: The protection function worked due to a DC voltage appearing at the speaker terminal.
A cause could be a defect in the amplifier.
Turning on the power without correcting the abnormality will cause the protection function to work in 3 seconds and the
power supply will be shut off.
www
.
http://www.xiaoyu163.com
PRI xxx
AD value is displayed, when the protection function is working
PRD xxx
AD value is displayed, when the protection function is working
x ao u163
y
i
2 9
8
Q Q
3 6 7 1 3 1 5
co
.
YMC-700/YMC-500
9 4 2 8
0 5 8 2 9 9 4 2 8
m
9 9
9 9
27