Pioneer VSX-LX52 Service Manual page 47

5
[2] Protection Circuit Process List (XPROTECT)
Item Purpose
AMP power supply circuit and
Transformer short circuit
detect. (defect status)
XPROTECT
Observe CN5701 pin3 or pin5
voltage, VL+ and VL-.
XPROTECT Circuit
H
POWER AMP ASSY
CN5701 CN5701
-3 -5
D5721 D5722
1SS352
1SS352
GAMP
J
DISPLAY ASSY
UCOM
IC3001
83
5
6
Detection Method
Detects when the XPROTECT
port becomes "L".
(Pin 83 of IC3001)
Short circuit detect:
Transformer
V+5_UST
Q5781
LTC124EUB
CN3001
-12
V+5_ST
C3016
0.047u/50
GNDU
6
7
Process Warning Indication
Turns muting on and
speaker relay off, and
None
immediately turns off the
power. Then flashes
MCACC indicator.
(*) To restore the previous status, follow the procedure
described in "How to Enter Release Mode" (P.49)
then turn the unit back on.
Short circuit detect:
AMP power supply circuit (VL)
VL+
V+5_UST
Q5783
LTA124EUB
Q5782
LTC124EUB
GNDU
CN5805
-5
CN8014
-5
D
COMPONENT ASSY
CN8005
-15
CN1250
-4
E
DIGITAL MAIN ASSY
CN1401
-28
VSX-LX52
7
8
Remarks
Once detected and turned
the power off, the power
cannot be turned on again.
(*)
V+5_UST
Q5784
LTA124EUB
R5784
Q5785
LTC124EUB
47k
UDZS7R5(B)
VL-
GNDU
D5782
GNDU
8
A
B
C
D
E
F
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