How To Diagnose The Amplifier Section - Pioneer VSX-52TX Service Manual

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7.1.2 HOW TO DIAGNOSE THE AMPLIFIER SECTION

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When DC detection worked (STBY IND. flashes for a long time)
3 7 63 1515 0
in the protection circuit of foregoing section (or there is not the
speaker output, probably only 1CH), failure (damage) of the
A
power amplifier section is considered.
Because this receiver cannot diagnose the amplifier section by an
electricity state by structure, please diagnose it in the following
steps.
Caution:
When release the STBY (flashes) state before repair, Because
there is the case that the damage progresses when turns the power
on once again, please be careful.
• According to a symptom, perform the following
B
confirmation beforehand.
1. Are not Fuse and IC protector opening it?
2-a. When can turn on electricity, confirm that supply voltage of
the point that can measure is appropriate.
2-b. Furthermore, confirm that voltage ((in a no signal) DC and
the appropriate signal output) between GND and R2008-
R2014 on the SP/PS Assy (Either of the amplifier side and
the speaker terminal side is possible) (Or remove either of
CN2101-2104) on the SP/PS Assy. And limit failure CH.
If was able to limit failure CH, diagnose the CH in the following
steps.
C
• Use the tester basically and check that each part is
not damaged (resistance value / open / short circuit).
About parts with damaged possibility, explain FL ch to an
TE
L 13942296513
example in order.
1. R4131, R4132 (ACN7132: 0.047 Ω, 0.5W chip drain resistor)
IC 4102, IC4103 (PBD001A: Nch, PBD002A: Pch output
POWER MOS Tr.) /POWER AMP-L Assy
2. R4119 (ACN7121: 0.18 Ω .5W ×2 cement source resistor)
R4117, R4118 (RS1/16S471J: 470 Ω chip resistor for
D
protection circuit)
D4101, D4103 (UDZS10B: 10V Zener diode for current
limiting)
D4102, D4104 (1SS355: Small signal diodes same as above)
R4110, R4111 (RS1/16S560J: 56 Ω chip gate resistor)
R4106, R4107 (RS1/16S101J:100 Ω chip IC4101 power filter
resistor) /POWER AMP-L Assy
3. IC4101 (PA9010A: Power amplifier with output current bias
Voltage step HIC) /POWER AMP-L Assy
4. Q2231 (2SA1514K) /VH TR Assy
E
Q2232 (2SC3906K) /VH TR Assy
Q2233 (2SA1837D1) /VH TR Assy
Q2234 (2SC4793D1) /VH TR Assy
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