Pioneer VSX-819H-K Service Manual page 32

1
A
Step 2: Operation of USB Media control IC
IC801 (pins 54,55)
XIN/XOUT
Is there
a 12 MHz
output?
Yes
B
CN802 USB_RX, TX (Pins 4, 5)
Do
USB_RX and USB_TX
communication with
main micom?
Yes
C
CN801 (pins 2,3)
D+/D-
Are
there the waveforms
D
like figure?
No
IC801 (pin 44) -> IC803 (pin 38)
After
turning the power
on and several seconds
later, does SDCLK change
12 MHz to 80 MHz?
Yes
E
Operation of IC801 is OK.
To STEP 3
F
32
1
2
Is
No
CN802 pins 1, 2, 3
(RESET, RDY, PDN)
high?
Yes
Check the parts and patterns in the path.
Replace XTAL1, etc.
No
USB_RX and USB_TX should
be high during operation.
Check the pattern in the path.
FRONT Assy and MAIN Assy
D+ and D- should have
waveform during normal
condition.
Check the pattern in the path.
IC801, etc.
Yes
Operation of IC801 is OK.
To STEP 3
Initial communication [SDCLK]
DATA and ADDRESS lines
No
between SDRAM (IC803),
FLASH ROM (IC802) and IC801
are may not be connected.
2
3
Check
No
CN705, CN704 of
FRONT and MAIN
Assy.
Yes
Fig. D+
X: 1 μS/div, Y: 2 V/div
VSX-819H-K
3
4
No
Check the path to
MAIN Assy.
Fig. D-
X: 1 μS/div, Y: 2 V/div
4