Pioneer 1014TX-K - THX Select A/V Receiver, Service Manual

Page: 118 / 149

VSX-52TX
118
1 2 3 4
1 2 3 4
C
D
F
A
B
E
8
6
6
7 c
b
a
POWER PROTECT Assy
• Jump with resistors.
• Turn on the power.
POWER PROTECT Assy
POWER PROTECT Assy
MAIN CONTROL Assy
6
Remove the Power Amplifier, leaving the POWER
PROTECT Assy intact.
• In this case, you can easily remove the Power
Amplifier if the FFC cable connecting the POWER
PROTECT Assy and the MAIN CONTROL Assy has
been disconnected on either side.
• When removing the POWER PROTECT Assy, pull out
the Assy while pushing on the board at the center from
the rear side, for easier removal with less stress on the
connector.
7
Jump with 100-ohm resistors in the following three
places on the POWER PROTECT Assy:
a
Between Pin 4 and Pin 5 of CN4052
b
Between Pin 5 and Pin 6 of CN4052
c
Between Pin 8 and Pin 9 of CN4051
8
Secure the POWER PROTECT Assy so that it will not
come into contact with metallic parts of the unit, such as
the chassis. Then connect the POWER PROTECT Assy
with the MAIN CONTROL Assy using an FFC cable and
turn on the power. The unit will be turned on without the
protection circuit activated.
9
After finishing diagnoses, remove the three resistors
inserted in Step
7
, and before returning the Power
Amplifier to its original position, discharge the electrolytic
capacitors in the places shown in the table below.
• If connection is made without discharging the electrolytic
capacitors, the resistors may be damaged by a surge of
current.
• Discharge the electrolytic capacitor using a resistor, not by
short-circuiting it. Using a tester, etc., completely
discharge it until there is no remaining voltage.
The board is easily removed
by pushing it in this direction.
Places to be discharged Discharging methods
SP/PS Assy: C2051, C2052 Jump with a discharging resistor in CN2002 of the SP/PS Assy. (Photo 1)
POWER AMP L Assy: C4401, C4402
Jump with a discharging resistor on the connector side of CN2002 of the POWER AMP-L Assy.
(Photo 2)
POWER AMP R Assy: C4403, C4404
While you still have CN2002 of the SP/PS Assy jumped with a discharging resistor, reconnect the
connector to CN2001 of the SP/PS Assy. (Photo 2)
TRANS 2-1 Assy: C2213, C2214 Jump between each capacitor and ground. (Photos 3 and 4)
• Remove the POWER PROTECT Assy.