Pioneer VSX-AX5Ai-S Service Manual page 144

1
How to Diagnose the Unit with the Heatsink Section Removed
With the following method, the Assys that cannot be diagnosed while the unit is powered because the Heatsink Section
obstructs access to them can be diagnosed.
A
Notes:
1. This method is merely an expedient way of diagnosing sections that are difficult to access, such as the MAIN CONTROL
Assy and REGULATOR Assy. Diagnoses involving the Power Amplifier section, such as DC detection, are not possible
with this method, nor are diagnoses regarding temperature detection.
2. After diagnosis is finished, discharge the electrolytic capacitor using a resistor, not by short-circuiting it.
Procedures
1
Remove the bonnet case 56B by removing the 23 screws.
2
Remove the two screws that secure Bridge Frames 45F and 45R.
3
Disconnect the six connectors connected between the Heatsink Section and the SP/PS Assy.
B
4
Disconnect the eight screws that secure the Heatsink Section.
5
Disconnect the three connectors of the POWER AMP IN Assy. In this case, you can easily remove the Assy once the flexible cable
connecting the POWER AMP IN Assy and the MAIN CONTROL Assy has been disconnected.
C
5
6
Remove the Heatsink Section, leaving the POWER AMP IN Assy intact.
7
Jump with a 22kΩ resistor between Pins 10 and 11 of CN4003 on the POWER AMP IN Assy.
8
Turn on the power. The power will then be on without the protection circuits activated.
D
7
Resistor (22kΩ)
E
CN4003
Diagnosis
F
144
1
2
POWER AMP IN Assy
5
5
5
POWER AMP IN
Assy
VSX-AX5Ai-S
2
3
When removing the POWER AMP IN Assy, pull out the Assy while
pushing on the board at the center from the rear, for easier
removal with less stress on the connector.
>
After finishing diagnosis, perform the following before
returning the Heatsink Section to its original position:
1
Remove the resistor used in Step 7.
2
Discharge the electrolytic capacitors on the VH line shown below.
If you do not, the resistors may be damaged by a surge of current.
Electrolytic capacitors to be discharged:
TRANS 2-1 Assy: C2207, C2208, C2211
FAN DRIVE Assy: C4055, C4056
3
Return the Heatsink Section to its original position.
3
4
See Step ¥.
4