Marantz PM-10 Service Manual page 55

[E] The PROT_6(M_B_DOWN, pin75) is the port to detect abnormalities of
the power supply circuit
(1) Detection of an abnormality in the LED power supply circuit.
When an undervoltage (around 11.3V) is detected in +15V of the LED power supply, [Q1004, Q1006]
turns off and "PROT_6" changes from "Hi → Lo".
If "PROT_6" changes from "Hi → Lo" when the above abnormality is detected, the protection circuit
activates. "POW_1 : pin72" and "POW_2 : pin73" change from "Hi → Lo" and power relay [S8501-S8503]
immediately turns off and shuts down.
The STANDBY indicator flickers to inform that an error has occurred.
This protection operation is intended for when a breakdown of the power supply circuit occurs and im-
mediately shuts off the power in order to avoid the risk of damage.
To check whether the power supply circuit is broken, turn off the unit, then wait for about 1 minute and
turn it on again.
This action will deactivate the protection operation.
If the "PROT_6" remains in the "Lo" abnormal state, which constitutes an abnormality, the unit shuts
down approximately 3 seconds later and the STANDBY indicator starts flickering.
If the protection operation is not deactivated even after the power is turned on again, the power supply
circuit or main transformer may be broken.
(Possible Factors)
· SHORT of ±20V type
+24V overcurrent detection for Relay
(Detection of a current of 133mA or
higher passing through +24V)
(Possible Factors)
· SHORT of ±20V type
± 20 V for pre AMP stage
Power supply fault detection
(Detection of an absolute value of 1.2V
for the midpoint electric potential)
(Possible Factors)
· SHORT of ±18V type
±18V for pre AMP stage
Power supply fault detection
(Detection of an absolute value of 1.2V
for the midpoint electric potential)
(Possible Factors)
· SHORT of +5V type
+5V for VOLUME · Q8108 destruction
Low Voltage/High voltage detection
(Detected when +5VA is 7V or more, 2V or less)
(Possible Factors)
· +15V series SHORT
· Main transformer connector missing etc.
+15V for LED
Low Voltage detection
(Possible Factors)
· DC generation on SPK output
SPK output DC detection
(Detected with ±2.2V or more)
(Possible Factors)
· Shut down SMPS
· Decrease ± HV by overload
±HV DIP detection
(Detected at 27V or less)
NC500
FATAL
(Detected at DC with output 15V or more)
(Possible Factors)
· DC generation on SPK output
(Possible Factors)
· Shut down SMPS
· Decrease ± HV by overload
NC500
±HV Under Voltage
(Detected at ±HV 30V or less)
(Possible Factors)
· SMPS pattern SHORT
NC500
±HV Over Voltage
(Detected with ±HV 101V or more)
NC500
VDR Under Voltage
(Detected at VDR 13.5V or less)
NC500
VDR Over Voltage
(Detected with VDR 19V or more)
(Possible Factors)
· Temperature rise of NC500 by the overload
NC500
Temperature
(Detection of a temperature of 90° C or
higher near the thermistor)
(Possible Factors)
· SPK output SHORT
NC500
SCCPIND (Detected at output 26A or more)
(25A min./26A typ./28A max.)
SMPS600
SMPS600Max output short circuit current(rail to rail) 7A DC *
Maximum power consumption 1100Wmax *
*) Limited by over current protection
SMPS600
Temperature detection
(Detects near the thermistor at 80 ℃ or higher)
55
PM-10S1 Protection Chart
PROT2
M_B_DOWN(PROT6)
PROT1
FATAL(PROT4)
Shut down SMPS
SMPS600
READY(PROT5)
Protection by PM10 circuit
Shut down SMPS
Protection by NC 500
Protection by SMPS 600
Shut down SMPS
UCOM