Yamaha RX-V681 Service Manual page 65

P1. SYSTEM MONITOR
This menu is used to display the A/D conversion value of the microprocessor which detects panel keys and protection
functions by using the sub-menu.
When "P1-6. KEY" sub-menu is selected, keys become inoperable due to detection of the values of all keys.
However, it is possible to advance to the next menu by pressing the "SCENE RADIO" (forward) key or "SCENE NET"
(reverse) key on the remote control.
* Numeric values in the figure are given as reference only.
P1-1. DC
Power amplifier DC (DC voltage) output is detected.
The voltage at 5 pin (DC_PRT) of IC78 is displayed.
Normal value: 32 to 74
(Reference voltage: 3.3 V=255)
* If DC becomes out of the normal value range, the protection function works to turn off the power.
P1-2. PS
Power supply voltage (PS) protection detection.
The voltage at 1 pin (PS1_PRT)/2 pin (PS2_PRT)/15 pin (PS3_PRT) of IC76 are displayed.
Voltage detects
PS1: AC12, AC-BL
PS2: ± 7V, +12V, +3.3T, +VP (PRV2_PROTECTION), -3.3V
PS3: +5.6V
Normal value
PS1: 51 to 179
PS2: 136 to 183
PS3: 126 to 177
(Reference voltage: 3.3 V=255)
* If PS1, PS2 or PS3 becomes out of the normal value range, the protection function works to turn off the pow-
er.
P1-1
DC: 50
P1-2
PS:117/160/154
PS3
PS2
PS1
RX-V681/RX-A760
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