Text preview for : Yamaha A-S300_500.pdf part of Yamaha integrated amplifier



Back to : Yamaha A-S300_500.rar | Home

INTEGRATED AMPLIFIER

A-S500/A-S300 SERVICE MANUAL



IMPORTANT NOTICE
This manual has been provided for the use of authorized YAMAHA Retailers and their service personnel.
It has been assumed that basic service procedures inherent to the industry, and more specifically YAMAHA Products, are already known
and understood by the users, and have therefore not been restated.
WARNING: Failure to follow appropriate service and safety procedures when servicing this product may result in personal injury,
destruction of expensive components, and failure of the product to perform as specified. For these reasons, we advise
all YAMAHA product owners that any service required should be performed by an authorized YAMAHA Retailer or
the appointed service representative.
IMPORTANT: The presentation or sale of this manual to any individual or firm does not constitute authorization, certification or
recognition of any applicable technical capabilities, or establish a principle-agent relationship of any form.
The data provided is believed to be accurate and applicable to the unit(s) indicated on the cover. The research, engineering, and service
departments of YAMAHA are continually striving to improve YAMAHA products. Modifications are, therefore, inevitable and
specifications are subject to change without notice or obligation to retrofit. Should any discrepancy appear to exist, please contact the
distributor's Service Division.
WARNING: Static discharges can destroy expensive components. Discharge any static electricity your body may have
accumulated by grounding yourself to the ground buss in the unit (heavy gauge black wires connect to this buss).
IMPORTANT: Turn the unit OFF during disassembly and part replacement. Recheck all work before you apply power to the unit.




CONTENTS
TO SERVICE PERSONNEL ............................................2 SELF-DIAGNOSTIC FUNCTION /


A-S500/A-S300
IMPEDANCE SELECTOR ...............................................3 .......................................21­27
FRONT PANELS .............................................................3 AMP ADJUSTMENT / .......................28­29
REAR PANELS ...........................................................4­8 IC DATA ...................................................................30­32
REMOTE CONTROL PANEL ..........................................9 PIN CONNECTION DIAGRAMS .............................33­34
SPECIFICATIONS / ................................... 9­10 BLOCK DIAGRAM ........................................................35
INTERNAL VIEW .......................................................... 11 PRINTED CIRCUIT BOARDS .................................36­52
SERVICE PRECAUTIONS / ..... 11 SCHEMATIC DIAGRAMS .......................................53­61
DISASSEMBLY PROCEDURES / ........... 12­15 REPLACEMENT PARTS LIST ................................63­79
UPDATING FIRMWARE / REMOTE CONTROL .....................................................80
..................................... 16­20




Copyright © 2010 All rights reserved.
1011 8 8 This manual is copyrighted by YAMAHA and may not be copied or
redistributed either in print or electronically without permission.
P.O.Box 1, Hamamatsu, Japan
'10.09
A-S500/A-S300


TO SERVICE PERSONNEL AC LEAKAGE
1. Critical Components Information WALL EQUIPMENT TESTER OR
Components having special characteristics are marked and OUTLET UNDER TEST EQUIVALENT
must be replaced with parts having specifications equal to those
originally installed.
2. Leakage Current Measurement (For 120V Models Only)
When service has been completed, it is imperative to verify
INSULATING
that all exposed conductive surfaces are properly insulated TABLE
from supply circuits.
· Meter impedance should be equivalent to 1500 ohms shunted · Leakage current must not exceed 0.5mA.
by 0.15 F. · Be sure to test for leakage with the AC plug in both polari-
ties.


For U model
"CAUTION"
"F1: FOR CONTINUED PROTECTION AGAINST RISK OF FIRE, REPLACE ONLY WITH SAME TYPE 8A (A-S500)
/ 6A (A-S300), 125V FUSE."
For C model
CAUTION
F1: REPLACE WITH SAME TYPE 8A (A-S500) / 6A (A-S300), 125V FUSE.
ATTENTION
F1: UTILISER UN FUSIBLE DE RECHANGE DE MÉME TYPE DE 8A (A-S500) / 6A (A-S300), 125V.




WARNING: CHEMICAL CONTENT NOTICE!
This product contains chemicals known to the State of California to cause cancer, or birth defects or other reproductive
harm.
DO NOT PLACE SOLDER, ELECTRICAL/ELECTRONIC OR PLASTIC COMPONENTS IN YOUR MOUTH FOR ANY REASON
WHATSOEVER!
Avoid prolonged, unprotected contact between solder and your skin! When soldering, do not inhale solder fumes or
expose eyes to solder/flux vapor!
If you come in contact with solder or components located inside the enclosure of this product, wash your hands before
handling food.



About lead free solder /
All of the P.C.B.s installed in this unit and solder joints are
soldered using the lead free solder.
Among some types of lead free solder currently available,
it is recommended to use one of the following types for
A-S500/A-S300




the repair work.
· Sn + Ag + Cu (tin + silver + copper)
· Sn + Cu (tin + copper)
· Sn + Zn + Bi (tin + zinc + bismuth)

Caution:
As the melting point temperature of the lead free solder
is about 30°C to 40°C (50°F to 70°F) higher than that of
the lead solder, be sure to use a soldering iron suitable
to each solder.




2
A-S500/A-S300


IMPEDANCE SELECTOR
WARNING:
Do not change the setting of the IMPEDANCE SELECTOR switch
when the unit power is switched on, as doing so may damage
the unit.




IMPEDANCE SELECTOR




FRONT PANELS
A-S500
A-S500 (U, C, R, T, A, B, G, L models)




A-S300


A-S500/A-S300
A-S300 (R, T, A, B, G, L, J models)




3
A-S500/A-S300


REAR PANELS
A-S500
A-S500 (U, C models)




A-S500 (R model)




A-S500 (T model)
A-S500/A-S300




4
A-S500/A-S300




A-S500
A-S500 (A model)




A-S500 (B model)




A-S500 (G model)


A-S500/A-S300




5
A-S500/A-S300




A-S500
A-S500 (L model)




A-S300
A-S300 (R model)




A-S300 (T model)
A-S500/A-S300




6
A-S500/A-S300




A-S300
A-S300 (A model)




A-S300 (B model)




A-S300 (G model)


A-S500/A-S300




7
A-S500/A-S300




A-S300
A-S300 (L model)




A-S300 (J model)
A-S500/A-S300




8
A-S500/A-S300


REMOTE CONTROL PANEL SPECIFICATIONS /
A-S500 A-S300 A-S500 A-S300

RAS5 Audio Section /
Minimum RMS Output Power (Power Amp. Section) /

(8 ohms, 20 Hz to 20 kHz, 0.019 % THD)
[A-S500] .............................................................. 85 W + 85 W
[A-S300] .............................................................. 60 W + 60 W
(6 ohms, 20 Hz to 20 kHz, 0.038 % THD)
[A-S500] (U, C, R, T, A, B, G models) .......... 100 W + 100 W
[A-S300] (U, C, R, T, A, B, G, J models) .......... 70 W + 70 W
Dynamic Power Per Channel / (IHF)
(8/6/4/2 ohms)
[A-S500] ..................................................... 130/150/185/220 W
[A-S300] ..................................................... 100/120/140/150 W
MAX Power Per Channel [B, G models]
(1 kHz, 0.7 % THD, 4 ohms)
[A-S500] ..........................................................................120 W
[A-S300] ............................................................................95 W
IEC Power [B, G models]
(1 kHz, 0.019 % THD, 8 ohms)
[A-S500] ..........................................................................100 W
[A-S300] ............................................................................75 W
Power Band Width /
[A-S500] (0.06 % THD, 42.5 W, 8 ohms) ........ 10 Hz to 50 kHz
[A-S300] (0.06 % THD, 30 W, 8 ohms) ........... 10 Hz to 50 kHz
Damping Factor / (SPEAKER-A)
1 kHz, 8 ohms ......................................................... 240 or more
Maximum Effective Output Power / (JEITA)
(1 kHz, 10 % THD)
[A-S500]
R, T, L models (8 ohms) ................................................130 W
R, T models (6 ohms) ....................................................150 W
[A-S300]
R, T, L, J models (8 ohms) ............................................100 W
R, T, J models (6 ohms) ................................................110 W
Input Sensitivity/Input Impedance /
PHONO (MM) .............................................. 3.0 mV / 47 k-ohms
CD, etc. ...................................................... 200 mV / 47 k-ohms
Maximum Input Signal / (1 kHz)
PHONO (MM) (0.003 % THD) ...........................60 mV or more
CD, etc. (0.5 % THD) ...........................................2.2 V or more
Output Level/Output Impedance /
REC OUT .......................................200 mV / 1.0 k-ohms or less
Headphone Jack Rated Output/Impedance /

CD, etc. (Input, 1 kHz, 200 mV, 8 ohms)
[A-S500] .................................................... 430 mV / 470 ohms



A-S500/A-S300
[A-S300] .................................................... 360 mV / 470 ohms
Frequency Response /
CD, etc. (20 Hz to 20 kHz) ........................................0 ±0.5 dB
CD, etc. Pure DIRECT ON (10 Hz to 100 kHz) .........0 ±1.0 dB
RIAA Equalization Deviation /
PHONO (MM) ................................................................. ±0.5 dB
Total Harmonic Distortion / (20 Hz to 20 kHz)
PHONO (MM) to REC OUT (3 V) ..................... 0.025 % or less
[A-S500]
CD, etc. to SP OUT (42.5 W, 8 ohms)
.......................................................................0.015 % or less
[A-S300]
CD, etc. to SP OUT (30 W, 8 ohms)
..................................................................... 0.015 % or less
Signal to Noise Ratio / (IHF-A Network)
PHONO (MM) (5 mV Input shorted) ................... 88 dB or more
CD, etc. (Pure DIRECT ON) (200 mV input shorted)
............................................................................ 100 dB or more


9
A-S500/A-S300




Residual Noise / (IHF-A Network) U ........................U.S.A. model B .......................British model
.............................................................................................30 V C ..................Canadian model G ..................European model
Channel Separation / R .....................General model L..................Singapore model
CD, etc. (Input 5.1 k-ohms shorted) T..................... Chinese model J .................. Japanese model
1 kHz ................................................................. 65 dB or more A .................Australian model
10 kHz ............................................................... 50 dB or more
Tone Control Characteristics /
BASS
Boost/Cut (50 Hz) ............................................................... ±10 dB
Turnover frequency ............................................................. 350 Hz iPhone, iPod, iPod classic, iPod nano and iPod touch are trademarks of
TREBLE Apple Inc., registered in the U.S. and other countries.
Boost/Cut (20 kHz) ............................................................. ±10 dB
Turnover frequency ............................................................ 3.5 kHz
Continuous Loudness Control /

Attenuation / (1 kHz) ............................................-30 dB
Gain Tracking Error /
(0 to -99 dB) ........................................................ 0.5 dB or less

A-S500 A-S300
General /
Power Supply /
U, C models ............................................................ AC 120 V, 60 Hz · DIMENSIONS /
R model ........................................AC 110-120/220-240 V, 50/60 Hz
T model ................................................................... AC 220 V, 50 Hz
(1-3/4")




25.5
(1")
A model .................................................................. AC 240 V, 50 Hz Top view
B, G models ............................................................ AC 230 V, 50 Hz
46


ø 60
L model ....................................................... AC 220-240 V, 50/60 Hz
J model .............................................................. AC 100 V, 50/60 Hz
Power Consumption /
[A-S500]
U, C models ............................................................ 240 W, 330 VA




387 (15-1/4")
341 (13-3/8")
R, T, A, B, G models ............................................................. 240 W
240 (9-1/2")




L model ................................................................................ 220 W
[A-S300]
R, T, A, B, G, L models ......................................................... 190 W
J model ................................................................................ 150 W
Standby Power Consumption /
................................................................................ 0.5 W or less
YID-W10 Standby Power Consumption (YID-W10 connect) /
YID-W10
................................................................................ 1.2 W or less
55
(2-1/8")




50 335 (13-1/4")
20.5
(3/4")
iPod Charge Power Consumption /
[A-S500] .................................................................. 35 W or less (2")
[A-S300] .................................................................. 25 W or less
Maximum Power Consumption [R model]
(1 kHz, 6 ohms, 10 % THD) Front view
[A-S500] ..........................................................................510 W
130 (5-1/8")
151 (5-7/8")



[A-S300] ..........................................................................400 W
A-S500/A-S300




AC Outlets / [J model]
[A-S300]
Switched x 2 .........................................................100 W max. total
Dimensions (W x H x D) /
21
(7/8")




..............................435 x 151 x 387 mm (17-1/8" x 6" x 15-1/4") 435 (17-1/8")
Weight /
[A-S500] ......................................................... 10.3 kg (22.7 lbs.)
[A-S300] ........................................................... 9.0 kg (19.8 lbs.)
Unit: mm (inch)
Finish /
Black color ................................. U, C, R, A, B, G, L, J models
Silver color ....................................... R, T, A, B, G, L, J models
Accessories /
Remote control ....................................................................... x 1
Battery (R6, AA, UM-3) .......................................................... x 2

* Specifications are subject to change without notice.




10
A-S500/A-S300


INTERNAL VIEW
A-S500 A-S300

Top view
1 2 3 4 5 6 7 8 1 OPERATION (1) P.C.B.
2 MAIN (6) P.C.B.
3 MAIN (5) P.C.B. (J model)
4 OPERATION (7) P.C.B. (R model)
5 MAIN (2) P.C.B.
6 DOCK P.C.B.
7 FUNCTION (2) P.C.B.
8 FUNCTION (3) P.C.B.
9 FUNCTION (1) P.C.B.
10 MAIN (4) P.C.B.
11 MAIN (1) P.C.B.
12 MAIN (3) P.C.B.
13 POWER TRANSFORMER
14 OPERATION (11) P.C.B.
15 OPERATION (8) P.C.B.
16 OPERATION (6) P.C.B.
17 OPERATION (3) P.C.B.
18 OPERATION (4) P.C.B.
19 OPERATION (5) P.C.B.
20 OPERATION (9) P.C.B.
13 12 11 10 9
21 OPERATION (2) P.C.B.
Front view 22 OPERATION (10) P.C.B.
14 15 16 17 18 19 20




22 21




SERVICE PRECAUTIONS /
A-S500/A-S300
Safety measures
· Some internal parts in this product contain high voltages
and are dangerous. Be sure to take safety measures
during servicing, such as wearing insulating gloves.
· Note that the capacitors indicated below are dangerous
even after the power is turned off because an electric
charge remains and a high voltage continues to exist
there.
Before starting any repair work, connect a discharging
resistor (5k-ohms/10W) to the terminals of each
capacitor indicated below to discharge electricity. The
time required for discharging is about 30 seconds per
each.
C134, C135 on MAIN (1) P.C.B.
For details, refer to "PRINTED CIRCUIT BOARDS: MAIN
(1) P.C.B.". 11
A-S500/A-S300


DISASSEMBLY PROCEDURES /
A-S500 A-S300

(Remove parts in the order as numbered.)
Disconnect the power cable from the AC outlet.


1. Removal of Top Cover
a. Remove 4 screws ( ), 4 screws ( ) and screw ( ).
(Fig. 1)
b. Remove the top cover. (Fig. 1)


2. Removal of Front Panel Unit
a. (A-S500)
Remove screw ( ), screw ( ) and then remove the
frame top. (Fig. 1)
(A-S300)
Remove screw ( ) and then remove the support top.
(Fig. 1)
b. Pull out the knobs and caps. (Fig. 1)
c. Remove 7 screws ( ). (Fig. 1)
d. Remove the front panel unit. (Fig. 1)




Top cover




(A-S500)
Frame top




Front panel unit
A-S500/A-S300




Cap POWER




Knob SP13
(A-S300)
Support top
Knob TC


Knob INPUT
Knob VOL

Cap DIRECT



Fig. 1
12
A-S500/A-S300




3. Removal of Sub-chassis Unit
a. Remove 2 screws ( ). (Fig. 2)
b. Remove CB101, CB108, CB503-505, CB706, CB851
and CB853-854. (Fig. 2)
c. Release 2 hooks and then remove the sub-chassis
unit. (Fig. 2)


4. Removal of FUNCTION (1)­(3) and DOCK P.C.B.s
a. Remove 8 screws ( ). (Fig. 3)
b. Remove screw ( ) and screw ( ). (Fig. 2)
c. Remove CB2, CB14, CB21 and CB506. (Fig. 2)
d. Remove the FUNCTION (1)­(3) P.C.B.s and DOCK
P.C.B. together. (Fig. 2)


FUNCTION (2) P.C.B.
DOCK P.C.B.


CB506
FUNCTION (3) P.C.B.


FUNCTION (1) P.C.B.
CB14 CB505
CB21 CB504
CB503
CB2
CB108
Sub-chassis unit




Hook
CB706
CB101
CB851




CB854
CB853
Hook




A-S500/A-S300
Fig. 2




Fig. 3

13
A-S500/A-S300




When checking the P.C.B.s:
· Put the rubber sheet and cloth over this unit. Then
place the sub-chassis unit on the cloth and check it.
(Fig. 4)
· Connect the ground point of the sub-chassis unit to
the chassis with a ground lead or the like. (Fig. 4)
· Reconnect all cables (connectors) that have been
disconnected.
· When connecting the flexible flat cable, be careful
with polarity.




Sub-chassis unit




Rubber sheet and cloth




Ground lead




Fig. 4
A-S500/A-S300




14
A-S500/A-S300




When checking the MAIN (1) P.C.B.:
· Spread the rubber sheet and the cloth. Then place
this unit on the cloth upside down. (Fig. 5)
· Remove 6 screws ( ) and then remove the chassis
cover. (Fig. 5)




Chassis cover




MAIN (1) P.C.B.




Rubber sheet and cloth




Fig. 5




A-S500/A-S300




15
A-S500/A-S300


UPDATING FIRMWARE /
A-S500 A-S300

When the following parts are replaced, the firmware must
be updated to the latest version.
FUNCTION P.C.B.
Microprocessor (IC502: FUNCTION P.C.B.)


Confirmation of firmware version
Before and after updating the firmware, check the
firmware version by using the self-diagnostic function
menu.
Start up the self-diagnostic function, have the
firmware version displayed, and note them down.
(See "SELF-DIAGNOSTIC FUNCTION")
* When the firmware version is different from written
one, perform the UPDATING FIRMWARE from the
beginning.


Initializing the back-up IC
(EEPROM: IC503 of the FUNCTION P.C.B.)
After updating the firmware, the back-up IC MUST be
initialized by the following procedure to have proper
memorization of the set up information.
Start up the self-diagnostic function.
(See "SELF-DIAGNOSTIC FUNCTION")
Set the SPEAKERS selector to the "A" position, press
the " " (power) key to turn off the power once and
press the " " (power) key to turn on the power again.
Then the back-up IC is initialized.


Required Tools
· Firmware downloader program
FlashSta.exe
· Firmware
A-S500/A-S300




ASx00_xxx.mot
ASx00_xxx.id
· RS-232C cross cable "D-sub 9 pin female"
(Specifications)

Pin No.2 RxD Pin No.2 RxD Pin No.2 RxD Pin No.2 RxD
Pin No.3 TxD Pin No.3 TxD Pin No.3 TxD Pin No.3 TxD
Pin No.5 GND Pin No.5 GND Pin No.5 GND Pin No.5 GND
Pin No.7 RTS Pin No.7 RTS Pin No.7 RTS Pin No.7 RTS
Pin No.8 CTS Pin No.8 CTS Pin No.8 CTS Pin No.8 CTS

· RS-232C conversion adaptor (Part No.: WR492800)




16
A-S500/A-S300




Preparation and precautions
· Download the firmware downloader program and
the latest firmware from the specified download
source to the same folder of the PC.
· Prepare the above specified RS-232C cross
cable.
· While writing the firmware, keep the other application
software on the PC closed.
It is also recommended to keep the software on the
task tray closed as well.


Connection
* Disconnect the power cable of this unit from the
AC outlet
· Set the switch (SW7) of RS-232C conversion
adaptor to the "FLASH UCOM" position. (Fig. 1)
· Connect the writing port (CB509 of the FUNCTION
P.C.B.) located on the rear panel of this unit to
the serial port (RS-232C) of the PC with RS-232C
cross cable, RS-232C conversion adaptor and
flexible flat cable as shown below. (Fig. 1)

This unit

PC




Writing port
Serial port (RS-232C) (FUNCTION P.C.B. CB509)
RS-232C conversion adaptor




RS-232C cross cable Flexible flat cable (9P)
FLASH
OTHER UCOM




A-S500/A-S300
SW7



Fig. 1




17
A-S500/A-S300




Operation procedure
1. Connect the power cable of this unit to the AC
outlet.
The power to this unit is supplied and the
microprocessor is in the writing mode.
2. Start up FlashSta.exe.
The screen appears as shown below. (Fig. 2)
3. Select the data to be transmitted and port. (Fig. 2)
· Select Program
Select Internal flash memory.
· RS-232C
Select the port of RS-232C
* For selection of the port, COM1 to 4 can be
used.
As COM5 or higher port cannot be used,
select out of COM 1 to 4 of the setting on the
PC side.




Select Internal flash memory




Select the port of RS-232C




Fig. 2



4. Click [Refer...] and select the firmware name. (Fig. 3)
* The ID and MCU Type are loaded
automatically when the file is selected. (Fig. 3)
Click [OK]. (Fig. 3)
A-S500/A-S300




When [Refer...] is clicked, the
"Open" screen appears.




Fig. 3
18
A-S500/A-S300




5. Click [Setting], and set the baud rate. (Fig. 4)




115200


40




Fig. 4




6. Click [E.P.R.], then the "Erase" screen appears. (Fig. 5)
7. Click [OK] to start writing. (Fig. 5)




Writing being executed. /




A-S500/A-S300
Fig. 5




19
A-S500/A-S300




8. When writing of the firmware is completed, the
screen appears as shown below. (Fig. 6)
Click [OK]. (Fig. 6)
9. Click [Exit] to end FlashSta.exe. (Fig. 6)




Fig. 6



10. Disconnect the power cable of this unit from the
AC outlet.
11. Remove the RS-232C conversion adaptor and
flexible flat cable from the writing port of this unit.
12. Connect the power cable of this unit to the AC
outlet, start up the self-diagnostic function and
check that the firmware version is the same
as written one. (See "Confirmation of firmware
version")
A-S500/A-S300




20
A-S500/A-S300


SELF-DIAGNOSTIC FUNCTION /
A-S500 A-S300

This unit has self-diagnostic functions that provides the
following functions.
· Indication of firmware version
· Indication of power management switch status
· Indication of protection information
· Initialization


Starting Self-Diagnostic Function
* Execute step 2 and 3 within 15 seconds after
executing step 1.
1. With the power to this unit turned on, press "
" (power) and "PURE DIRECT" switches to turn
them off respectively. (Fig. 1)
2. Repeat pressing "PURE DIRECT" switch to turn it
ON/OFF 3 times. (Fig. 1)
3. Press the " " (power) switch inward to turn on the
power. (Fig. 1)
The self-diagnostic function mode is activated.



2. "PURE DIRECT" switch
1 2 3




OFF ON OFF ON OFF ON OFF




A-S500/A-S300
3. " "(power) switch




OFF ON/
STANDBY



Fig. 1




21
A-S500/A-S300




Indication provided when Self-
Diagnostic Function started

1. Indication of firmware version




POWER ON indicator



INPUT indicators



3. Indication of protection information 2. Indication of power management switch status


Fig. 2




Details of Indication
1. Indication of firmware version
The firmware version of the microprocessor (IC502
of the FUNCTION P.C.B.) is indicated in the binary
code (BCD) using the INPUT indicators.

Firmware version /
INPUT indicators /

Binary number (BCD) [Light up: 1, Off: 0] /
CD TUNER DOCK PHONO Decimal number /
(23 = 8) (22 = 4) (21 = 2) (20 = 1)
0 1 1 0 V0006 (4+2=6)
0 1 1 1 V0007 (4+2+1=7)
1 0 0 0 V0008 (8)
· ·
· ·
· ·
A-S500/A-S300




Fig. 3



2. Indication of power management switch
status
The status (ON/OFF) of the POWER MANAGEMENT
switch located on the rear panel is indicated
using the "LINE 3" INPUT indicator.
Light up: POWER MANAGEMENT switch is ON
Off: POWER MANAGEMENT switch is OFF




22
A-S500/A-S300




3. Indication of protection information
The protection information is indicated by the
flashing pattern of the " "(POWER ON) indicator.


Types of protection function / MAIN ZONE indicator flashing pattern / : Lit /
: Off /

PS protection / Flashing 2 /
500mS 500mS 500mS 1000mS 500mS 500mS 500mS 1000mS 500mS


I protection / Flashing 3 /
500mS 500mS 500mS 500mS 500mS 1000mS 500mS 500mS 500mS 500mS


DC protection / Flashing 4 /
500mS 500mS 500mS 500mS 500mS 500mS 500mS 1000mS 500mS 500mS


TMP protection L/R ch / Flashing 5 /
500mS 500mS 500mS 500mS 500mS 500mS 500mS 500mS 500mS 1000mS


APD (Automatic Power Down) / Flashing 6 /
500mS 500mS 500mS 500mS 500mS 500mS 500mS 500mS 500mS 500mS 500mS

Normal
Lit up/
(no protection function) /
Continuous



Fig. 4




PS (Power Supply) protection
Cause: The voltage in the power supply
section is abnormal.
Normal value: 2.357 to 3.257V
Detection port: PRV (FUNCTION P.C.B. 93 pin of
the microprocessor IC502)
Detected at: ACL, ±15, +5S

I protection L/Rch
Cause: Excess current flow into amplifier.
Speaker terminal shorted. (*)
Normal value: LOW (0V)


A-S500/A-S300
Detection port: PRI (FUNCTION P.C.B. 73 pin of
the microprocessor IC502)
Detected at: PRI (Amplifier output L/Rch of
MAIN P.C.B.)
* If the protection function works due to shortage
at the speaker terminal, the power turns off at
the excess current protection L/Rch.
However, pressing the " " (power) switch for
OFF/ON, all INPUT indicators flash 5 times
and the power to turn on.




23
A-S500/A-S300




DC voltage protection
Cause: Abnormal DC voltage of amplifier
output.
Normal value: 0.947 to 2.517V
Detection port: PRD (FUNCTION P.C.B. 89 pin of
the microprocessor IC502)
Detected at: Amplifier output L/Rch of MAIN
P.C.B.

THM protection L/Rch
Cause: Abnormal temperature of heat
sink.
Normal value: 0.20 to 1.66V
Detection port: THML (FUNCTION P.C.B. 84 pin
of the microprocessor IC502)
THMR (FUNCTION P.C.B. 83 pin
of the microprocessor IC502)
Detected at: THML (Heat sink temperature
detection Lch IC101 of the MAIN
P.C.B.)
THMR (Heat sink temperature
detection Rch IC102 of the MAIN
P.C.B.)




Canceling Self-Diagnostic Function
To keep memory of the back-up IC preserved
Set the SPEAKERS selector to the OFF, B or A+B
position and press the " " (power) switch to turn off
the power. (Fig. 6)
Self-diagnostic function is canceled.

To reserve initialization of the back-up IC
Set the SPEAKERS selector to the "A" position, press
the " " (power) switch to turn off the power. (Fig. 6)
Self-diagnostic function is canceled with the initialization
reserved.
A-S500/A-S300




24
A-S500/A-S300




Starting in the Protection Cancel mode
If the protection function works and causes hindrance
to trouble shoot, cancel the protection function as
described below, and it will be possible to enter the
self-diagnostic function mode.
(The protection functions other than the excess
current detect function will be disabled.)
* Execute step 2 and 3 within 15 seconds after
executing step 1.
1. With the power to this unit turned on, press " "
(power) and "PURE DIRECT" switches to turn them
off respectively. (Fig. 5)
2. Repeat pressing "PURE DIRECT" switch to turn it
ON/OFF 6 times. (Fig. 5)
3. Press the " " (power) switch inward to turn on the
power. (Fig. 5)
4. Press the "PURE DIRECT" switch inward to the
ON position. (Fig. 5)
After a few seconds, the self-diagnostic function
mode is activated with the protection functions
disabled.
In this mode, the "LINE 2" INPUT indicator flashes
to indicate that the mode is self-diagnostic 2. "PURE DIRECT" switch
function mode with the protection functions 1 6
disabled. (Fig. 5)
.........


OFF ON OFF ON OFF




A-S500/A-S300
INPUT indicators

3. " "(power) switch
4. "PURE DIRECT" switch




OFF ON/
STANDBY OFF ON


Fig. 5


CAUTION!
· Using this product with the protection function
disabled may cause further damage to this unit. Use
special care for this point when using this mode.


25
A-S500/A-S300




Note)
· Applying the power to this unit without correcting the
abnormality can be dangerous and cause additional
circuit damage. To avoid this, if protection function
has been activated the number of times which is set
beforehand, the power will not turn on even when the
" " (power) switch is pressed. In order to turn on the
power again, disconnect the power cable of this unit
from the AC outlet once and then reconnect it again.
· The output transistors in each amplifier channel
should be checked for damage before applying
power to this unit.
· Amplifier current should be monitored by measuring
DC voltage across the emitter resistors for each
channel.
· Set this unit once to the "factory reset" state before
turning on the power again. (For more information,
refer to "Initialization" of SELF-DIAGNOSTIC
FUNCTION.)




PS (Power Supply) protection:
If protection function has been activated 3 times
consecutively, the power will not turn on.

I protection L/Rch:
If protection function has been activated 1 time,
the power will not turn on.
* However, the power turns on when the
protection function worked due to short at the
speaker terminal.

Amplifier DC voltage protection L/Rch:
If protection function has been activated 3 times
consecutively, the power will not turn on.

THM protection L/Rch:
The power turns on no matter how many times the
protection function has worked.
A-S500/A-S300




26
A-S500/A-S300




Initialization
This operation initializes the back-up IC to return
the settings below to those when shipped from the
factory.
a. INPUT (CD)
b. Protection history (None)
c. Number of times when protection is detected (0
times)
* In the parentheses ( ) are settings when
shipped from the factory.

· Operation Procedures
With the self-diagnostic function activated, follow
the steps below.
1. Set the SPEAKERS selector to the A position.
(Fig. 6)
2. Press the " " (power) switch to turn off the
power once.
3. Press the " " (power) switch inward to turn on
the power again.
The settings above return to those when
shipped from the factory and "CD" of the
INPUT indicators lights up. The power relay
turns on in a few seconds and the normal
operation is restored.



1. SPEAKERS selector




A-S500/A-S300

INPUT indicators
2. " "(power) switch 3. " "(power) switch




ON/ OFF OFF ON/
STANDBY STANDBY




Fig. 6


27
A-S500/A-S300


AMP ADJUSTMENT /
A-S500 A-S300

CONFIRMATION OF IDLING CURRENT
1. Right after power is turned on, confirm that the
voltage across the terminals of R160 (L ch) and
R161 (R ch) are between 0.1 mV and 10 mV.
2. If measured voltage exceeds 10 mV, open (cut off)
R139 (L ch), R142 (R ch) and reconfirm the voltage.
Attention
If the measured voltage exceeds 10 mV after
repairing the power amplifier, check other parts
again for any possible defect before cutting the
resistor.
3. Confirm that the voltage is between 0.2 mV and
15 mV after 60 minutes.


0.1mV­10mV
(L ch)



Cut off

0.1mV­10mV
(R ch)



R160 R139 (L ch)
R142 (R ch)




R161



MAIN (1) P.C.B.
A-S500/A-S300




R160 R161

R139
R142




28
A-S500/A-S300




SCHEMATIC DIAGRAM

MAIN (1)




R160




L ch
R139




Cut off
0.1 mV ­ 10 mV