Denon MC6000MK2EM Service Manual page 53

1-8 No sound input/output from USB
Symptom: Audio is not input/output :
Diagnostic procedure:
1.Connect PC with USB cable.
2.Is there clock 6MHz to ground IC901->PIN51&50 If it is not, IC901、X900 is damaged.
3.Is a signal input to the USB D+ & D- ? IC901 USB IN->PIN7& PIN8 , as figure 1-8
4.If it is not, IC901 is damaged.
1-8 IC901 PIN7& PIN8
1-9 No sound output from MASTER OUT
Symptom: Audio is not output & MASTER level meter is not light up :
Diagnostic procedure:
1.Is a signal output to the DAC? U755:MASTER->PIN15&PIN18
A. If it is, something is wrong with the analog -circuit block. Check if output amplifier (U515:MASTER) is
working normally. Check if each MUTE transistor (Q512~513) BASE PIN is -12V.
B. If it is not, something is wrong with the digital-circuit block. Check if there is CLOCK signal for
U755 :MASTER->PIN1 & PIN2 & PIN3 & PIN4 , as figure 1-9.
1-10 No sound output from BOOTH
Symptom: Audio is not output :
Diagnostic procedure:
1. Is a signal output to the DAC? U756:BOOTH->PIN15 & PIN18
A. If it is, something is wrong with the analog -circuit block. Check if output amplifier (U510)
is working normally. Check if each MUTE transistor (Q526~Q529) BASE PIN is -12V.
B. If it is not, something is wrong with the digital-circuit block. Check if there is CLOCK signal for
U756:BOOTH ->PIN1 & PIN2 & PIN3 & PIN4, as figure 1-9.
1-9 U755 PIN 1
1-9 U755 PIN 4
1-9 U755 PIN 2
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1-9 U755 PIN 3