Pioneer krp-m01, Service Manual

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10 8
KRP-M01
1 2 3 4
A
B
C
D
E
F
1 2 3 4
Note on Removin g the POWER SUPPLY Unit from the Chassis
and Method for Resettin g Standby Power Latchup
How to remove the POWER SUPPLY Unit
For 3-5 minutes after the unit is turned off, residual electric charge remains in the C310 capacitor on the PO W ER SUPPLY
Unit. Before removing the PO W ER SUPPLY Unit from the chassis, be sure to confirm that residual charge inside the PO W ER
SUPPLY Unit has become sufficiently low. ( W ithout forced discharge, residual charge that remains after 3-5 minutes will fall to
one-tenth or less, which is still about 20 V . Therefore, even after the PO W ER SUPPLY Unit is removed, it is recommended to
perform forced discharge on the PO W ER SUPPLY Unit, as shown below.)
For quick removal of residual charge, forced discharge is recommended, using two 220 ohm/10 W resistors (440 ohm/20 W ).
1. Make sure that the AC power cord is unplugged. Using a tester, check the voltage between the + terminal of RC101 bridge
diode and Q301 radiator (equivalent to the voltage between two electrodes of C310).
2. Let the unit sit for more than 5 minutes until the voltage equivalent to that between two electrodes of C310 falls to under 20 V .
3. After checking that the voltage is under 20 V , disconnect the connectors of the PO W ER SUPPLY Unit and remove the PO W ER
SUPPLY Unit.
4. Using two resistors mentioned above, completely discharge residual charge from C310.
How to reset Standby power latchup
(In a case where the protection a
g ainst Standby power excess volta g e is activated)
1. After removing the causes of the malfunction, short-circuit between the J W 1 and J W 2 jumpers.
2. If the PO W ER SUPPLY Unit functions properly, after opening the above jumpers, the unit starts up.
After checking that the voltage at the measurement points
(equivalent to the voltage between two electrodes of C310)
is under 20
V , remove the PO W ER SUPPLY Unit.
Then, completely discharge residual charge, using resistors.
Site where power-down is detected
(Pin 3 of C N 801)
Q301 radiator
Secondary radiator
C603
+ side – side
C310
C310
J W 1
J W 2
RC101 + terminal
(lead)
To forcibly reset latchup of STBY3.4 V , short-circuit between J W 1 and
J W 2 (near C603), using a flathead screwdriver or similar object.
If the causes of the malfunction are removed, after opening the jumpers, the unit starts up.
SIDE B