Yamaha n8 Service Manual page 139

TL257 (L:MUTE-REQ)
L:MUTE-REQ is a signal that mutes analog output and
audio output to IEEE1394 (DAW I/O) when request for
muting is produced from the MLAN circuit board.
When the point is "L" level (0 V), all muting circuits
are activated and mute circuit in MLAN circuit board,
mute circuit before D/A converter and mute circuit for
analog output execute muting operation.
Deactivation of muting is controlled by the firmware
and the level is "H" (+3.3 V).
Normally, the level is at "L" when the power is turned
ON/OFF, sampling frequency is changed, or bus reset
of IEEE1394 is produced.
The reference GND for observing/measuring the point
is TL258 (DGND).
• Overall View
1)
2)
7)
5)
1) Power supply voltage
2) A/D input
3) A/D output
4) 5)
6)
2)
4) 1)
4) D/A input
5) D/A output
6) Audio synchronized clock
TL257
7)
4)
3)
3)
6)
3)
3)
6)
7) Muting control
n8/n12
1)
1)
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