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IMPORTANT NOTICEThis manual has been provided for the use of authorized Yamaha Retailers and their service personnel. It has been assumed thatbasic service procedures inherent to the industry, and more specifically Yamaha Products, are already known and understood by theusers, 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, weadvise all Yamaha product owners that all service required should be performed by an authorized Yamaha Retaileror the appointed service representative.
IMPORTANT: The presentation or sale of this manual to any individual or firm does not constitute authorization, certification orrecognition 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, andservice departments of Yamaha are continually striving to improve Yamaha products. Modifications are, therefore, inevitable andchanges in specification are subject to change without notice or obligation to retrofit. Should any discrepancy appear to exist, pleasecontact the distributor's Service Division.
WARNING: Static discharges can destroy expensive components. Discharge any static electricity you body may haveaccumulated 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.
WARNING: CHEMICAL CONTENT NOTICE!The solder used in the production of this product contains LEAD. In addition, other electrical/electronic and /or plastic (where applicable)components may also contain traces of chemicals found by the California Health and Welfare Agency (and possibly other entities) tocause cancer and/or birth defects or other reproductive harm.
DO NOT PLACE SOLDER, ELECTRICAL/ELECTRONIC OR PLASTIC COMPONENTS IN YOUR MOUTH FOR ANY REASON WHAT-SOEVER!
Avoid prolonged, unprotected contact between solder and your skin! When soldering, do not inhale solder fumes or expose eyes tosolder/flux vapor!
If you come in contact with solder or components located inside the enclosure of this product, wash your hands before handling food.
1. Top Cover1-1 Remove the nine (9) screws marked [410]. The top cover
can then be removed. (Fig. 1, 2)
2. Power Transformer2-1 Remove the top cover. (See Procedure 1.)2-2 Remove the four (4) screws marked [70]. The power
transformer can then be removed. (Fig. 1)
5. Front Panel 5-1 Remove the top cover. (See Procedure 1.)5-2 Remove the two (2) screws marked [380a] and the two (2)
screws marked [380b]. The front panel can then be removed.(Fig. 3)
6. SUB 3/5 Circuit Board6-1 Remove the top cover. (See Procedure 1.)6-2 Remove the front panel. (See Procedure 5.)6-3 Remove the two (2) screws marked [220]. The SUB 3/5
circuit board can then be removed. (Fig. 3)
1/5
2/5
3/5
4/5
3. SUB7 1/5 Circuit Board3-1 Remove the top cover. (See Procedure 1.)3-2 Remove the six (6) screws marked [80a]. The SUB 1/5
circuit board can then be removed. (Fig. 1)
4. SUB 2/5 Circuit Board4-1 Remove the top cover. (See Procedure 1.)4-2 Remove the six (6) screws marked [50a] and the two (2)
screws marked [50b]. The SUB 2/5 circuit board can then be removed. (Fig. 2, 7)
7. SUB 4/5 Circuit Board7-1 Remove the top cover. (See Procedure 1.)7-2 Remove the front panel. (See Procedure 5.)7-3 Remove the two (2) screws marked [200]. The SUB 4/5
circuit board can then be removed. (Fig. 3)
8. DC Fan8-1 Remove the top cover. (See Procedure 1.)8-2 Remove the front panel. (See Procedure 5.)8-3 Remove the four (4) screws marked [150]. The DC fan
can then be removed. (Fig. 3)
[220]: Bind Head Tapping Screw-B 3.0X8 MFZN2BL (EP600190) [380]: Bind Head Tapping Screw-B 4.0X8 MFZN2BL (EG340190)
[70] 4
[80a] 6 [410]
[410]
[410]
[410]
[410]
[410]
Top cover
Power Transformer
[410] Rear panel
[380a]
[380a]
[380b] [380b]
[50a] [50a]
[50b]
(Fig. 1) (Fig. 2)
(Fig. 3)
[200] [220] [150]
[150]
Front panel
DC Fan
[70]: Bind Head Screw SP 5.0X10 MFZN2BL (VU688100) [80]: Bind Head Tapping Screw-B 3.0X8 MFZN2BL (EP600190) [410]: Bind Head Tapping Screw-B 4.0X8 MFZN2BL (EG340190)
[50a]: Bind Head Screw A4.0X8 MFZN2BL (VP156800) [410]: Bind Head Tapping Screw-B 4.0X8 MFZN2BL (EG340190)
DISASSEMBLY PROCEDURE
8
XS250/350
PA7
[60a]: Bind Head Screw SP 3.0X8 MFZN2Y (EG330290) [80b,c]: Bind Head Tapping Screw-B 3.0X12 MFZN2BL (VQ074600)
10. PA7 Circuit Board10-1 Remove the top cover. (See Procedure 1.)10-2 Remove the front panel. (See Procedure 5.)10-3 Remove the PA7 unit. (See Procedure 9.)10-4 Remove the sixteen (16) screws marked [80b]; the four
(4) screws marked [80c] and the six (6) screws marked [60a]. The PA7 circuit board can then be removed. (Fig. 6)
9. PA7 Unit9-1 Remove the top cover. (See Procedure 1.)9-2 Remove the front panel. (See Procedure 5.)9-3 Remove the four (4) screws marked [250]. The PA7 unit
with the chassis can then be removed. (Fig. 4)9-4 Remove the eight (8) screws marked [130]. The PA7 unit
11. Rear Assembly11-1 Remove the top cover. (See Procedure 1.)11-2 Remove the six (6) screws marked [270]. The rear assembly
can then be removed. (Fig. 7)
12. SUB 5/5 Circuit Board12-1 Remove the top cover. (See Procedure 1.)12-2 Remove the rear assembly. (See Procedure 11.)12-3 Remove the four (4) screws marked [440] and the two (2)
screws marked [50b] and the two (2) screws marked [60b]. The SUB 5/5 circuit board can then be removed. (Fig. 7)
(Fig. 7)
2/5
5/5
[440] 2
Cover, Speaker terminal
Rear panel
[440] 2
[50a] 4
[50a] 2
[70b] 2
[60b] 2
[50b] 2
[50a]: Bind Head Screw A4.0X8 MFZN2BL (VP156800) [50b]: Bonding Tapping Screw-B 3.0X8 MFZN2BL (VN413300) [60b]: Bind Head Tapping Screw-B 3.0X12 MFZN2BL (VQ074600) [70a]: Bind Head Screw SP 5.0X10 MFZN2BL (VU688100) [70b]: Bind Head Tapping Screw-B 3.0X8 MFZN2BL (EP600190) [440]: Bind Head Tapping Screw-B 3.0X8 MFZN2BL (EP600190)
A STEREO and PARALLEL OperationBefore performing any following adjustments, set the unit as follows:1. Set the ATTENUATIONS at the MAX.2. Input terminal: Cannon connector pin 2 is HOT, pins 1 and 3 GROUND.3. MODE switch: STEREO4. Output terminal: RL = 4 ohm/more than 500 W5. Others: Both Channel operation is required, if no particular indication. Moreover, turn off the filter switch,
if no particular indication.
Adjustment Specifications1. Fan TestWhen turning on the power switch, confirm that both fans of right and left sides regulate at low speed.
2. Muting TestAfter applying power to the unit, the PROTECTION indicator should remain ON 2.5 +/-1 seconds to indicate that the protection circuitry is operating and the indicator should go out. NO signal is output while this indicator lit.
3. Idle Current TestConnect the input terminal to the GROUND and adjust the VR201 (A channel) and VR301 (B channel) that the DC voltage Vb between the pin 1 and pin 2of the CN202 (A channel) and the CN302 (B channel) should be 1.0 +/-0.2 mV. And After finishing all tests, adjust the Vb again to 1.0 +/-0.2 mV.
4. Input Terminal DC offsetConnect the input terminal to the GROUND and check that the DC voltage Vdc of the output terminal should be 0 +/-75 mV.
5. Gain TestCheck that the OUTPUT should be +22.1 +/-0.5 dBu, when a sine wave of 1 kHz at -10 dBu is applied to the INPUT. This test should be performed on PARALLEL operation.
6. Frequency Response TestFilter switch OFF:When a sine wave of 20 Hz, 1 kHz or 20 kHz at -10 dBu is applied to the INPUT, check that the output is 0 +/-0.5 dB at 20 Hz and -0.5 +/-0.5 dB at 20 kHz taking the 1 kHz as a reference.Filter switch SUB WOOFER:<MIN>When a sine wave of 25 Hz, -10 dBu is applied to the INPUT, check that the output is -3.5 +/-1.0 dB taking the 1 kHz as a reference at the filter switch OFF.<MAX>When a sine wave of 150 Hz, -10 dBu is applied to the INPUT, check that the output is -3.5 +/-1.0 dB taking the 1 kHz as a reference at the filter switch OFF.
Filter switch LOW CUT:<MIN>When a sine wave of 25 Hz, -10 dBu is applied to the INPUT, check that the output is -4.5 +/-1.0 dB taking the 1 kHz as a reference at the filter switch OFF.<MAX>When a sine wave of 150 Hz, -10 dBu is applied to the INPUT, check that the output is -3.5 +/-1.0 dB taking the 1 kHz as a reference at the filter switch OFF.
INSPECTIONS
14
XS250/350
7. Harmonic Distortion TestWhen a high quality sine wave is applied at 20 Hz, 1 kHz or 20 kHz, the harmonic distortion should be as follows:
*This test should have been finished within 30 minutes.
8. Channel Separation Test8-1 Apply a -5 dBu, 20kHz sine wave into the channel A.8-2 Short the input for the channel B with a 600 ohm load.8-3 Set the output of the channel A at a reference of 0 dB.8-4 If channel B attenuator is set to the same as channel A, channel B output should be l ess than -65 dB. (RL = 8 ohm)
9. Noise Test9-1 Set the input attenuator to MAX.9-2 Short the input with a 600 ohm load.9-3 Measure at the output, noise level should be less than -65 dBm.9-4 Set the input attenuator to "∞", noise level should be less than -70 dBu.*Be careful that it is not affected by noise induced during this inspection.
10. Stability TestWhen a rectangular wave 10 kHz, -10 dBu is applied to the input and a capacitor 10 pF–0.47 µF is connected with 4 ohm load resistor in parallel, the overshoot and the ringing should be as follows. Oversshoot: Vp/Vo </= 1.8 Ringing: less than 5 wavesNext, when the 4 ohm load resistor is removed and the load is the capacitor 10pF–0.47 µF only, the overshoot and the ringing should be as follows. Oversshoot: Vp/Vo </= 2.5 Ringing: fade away in less than 7 waves and no oscilation
11. Protection Circuitry TestCheck that the relay does not work when you apply a sine wave of +5.0 dBu (XS350), +3.0 dBu (XS250) at 10 Hz to the input and adjust the input level to obtain a clipped output wave form.Next, check that when you apply a sine wave of 1 Hz, 0.0 dBu to the input, the signal is cut off within 2 seconds, and the PROTECTION indicator should light up.Finally, check that when no signal is applied, the amplifier would resume to normal operation within 10 seconds.
12. PC Limiter Circuitry TestCheck that the OUTPUT should be as follows with an oscilloscope when a sine wave of 0 dBu (XS350), -1.5 dBu (XS250) at 1 kHz is applied to the INPUT and the output is shorted with a 1 ohm load ( +/-5%). At this time, check the CLIP indicator lights.
*This test should have been finished within 30 minutes.
20 kHz350 W + 350 W (33.7 dBu/ch)250 W + 250 W (32.2 dBu/ch)
13. Signal Indicator TestWhen a sine wave of 1 kHz, -23 dBu is applied to the input, SIGNAL indicator should light up.
B BRIDGE OperationBefore performing any following adjustments, set the unit as follows:1. Set the ATTENUATIONS at MAX.2. Input terminal: Cannon connector pin 2 is HOT, pins 1 and 3 GROUND.3. MODE switch: BRIDGE4. Output terminal: (A ch+, B ch+) RL = 4 + 4 ohm/more than 500 W5. Connection for measuring: Measure the output at the point as shown below.
Adjustment Specifications1. Gain TestCheck that the OUTPUT should be +22.1 +/-1.0 dBu, when asine wave of 1 kHz at -10 dBu is applied to the INPUT.
2. Frequency Response TestWhen a sine wave of 20 Hz, 1 kHz or 20 kHz at -10 dBu is applied to the INPUT, check that the output is 0 +/-0.5 dB at 20 Hz and -0.5 +/-0.5 dB at 20kHz taking the 1 kHz as a reference.
3. Harmonic Distortion TestWhen a high quality sine wave is applied at 20 Hz, 1 kHz or 20 kHz, the harmonic distortion should be as follows:
4. Noise Test9-1 Set the input attenuator to "0".9-2 Short the input with a 600 ohm load.9-3 Measure at the output, noise level should be less than -60 dBm. (LR = 8 ohm)9-4 Set the input attenuator to "∞", noise level should be less than -60 dBu*Be careful that it is not affected by noise induced during this inspection.
C Settings after the testThe attenuator should set to "∞".
The MODE switch should set to STEREO.
D Others0 dBu = 0.775 VWhen measuring noise level,use a DIN audio filter.
*This test should have been finished within 30 minutes.
XS350XS250
Power output level(4 ohm)
33.7 dBu32.2 dBu
THD20 Hz 1 kHz 20 kHz
</= 0.1 % </= 0.1 % </= 0.1 %
+
-
MEASURINGINSTRUMENT
4 Ω
4 Ω
SPEAKERS
CHANNEL B
GND
INPUTCHANNEL A
POWER AMPLIFIER
XS250/350PARTS LIST
• The numbers in “QTY” shows quantities for each unit.• The parts with “--” in “Parts No.” are not available as spare parts.• The mark “ ” in the remarks column indicates that these parts are interchangeable.
Notes: DESTINATION ABBREVIATIONS
A : Australian model J : Japanese modelB : British model U : U.S. modelC : Canadian model V : General export model(110V)E : European model W : General export model(220V)H : North European model X : General export modelI : Indonesian model Y : Export model
WARINIGConponents having special characteristics are marked and must be replacedwith parts having specifications equal to those originally installed.
XS350 XS250 XS350 U,V (V294020)XS350 H,W (V294030)XS350 B (V294040)XS350 A (V294050)XS250 U,V (V294060)XS250 H,W (V294070)XS250 B (V294080)XS250 A (V294090)
(V294280) U,V H,W,A B XS350 U,V XS350 H,W,B XS350 A XS250 U,V XS250 H,W,B XS250 A
(V288350) XS350 XS250
(V288370)(VV10460)
XS350 U,V XS350 H,W,B XS350 A XS250 U,V XS250 H,W,B XS250 A XS350 U,V XS350 H,W,B XS350 A XS250 U,V XS250 H,W,B XS250 A XS350 U,V (XV419B0) XS350 H,W,B,A (XV419B0)XS250 U,V(XV419B0)XS250 H,W,B,A(XV419B0)XS350(XV419B0)XS250(XV419B0)XS350(XV419B0)
Metal Film Resistor Carbon Resistor Metal Film Resistor Metal Film Resistor Metal Film Resistor Carbon Resistor Carbon Resistor Metal Film Resistor Metal Film Resistor Metal Film Resistor Carbon Resistor Metal Film Resistor Metal Film Resistor Carbon Resistor Carbon Resistor Metal Film Resistor Metal Film Resistor Carbon Resistor Metal Film Resistor Carbon Resistor Metal Film Resistor Metal Film Resistor Metal Film Resistor Carbon Resistor Metal Film Resistor Metal Film Resistor Carbon Resistor Metal Film Resistor Metal Film Resistor Carbon Resistor Metal Film Resistor Metal Film Resistor Carbon Resistor Carbon Resistor Metal Film Resistor Metal Film Resistor Metal Film Resistor Carbon Resistor Carbon Resistor Metal Film Resistor Carbon Resistor Carbon Resistor Carbon Resistor Carbon Resistor Carbon Resistor Carbon Resistor Carbon Resistor Carbon Resistor Carbon Resistor Carbon Resistor Carbon Resistor Carbon Resistor Carbon Resistor Carbon Resistor Carbon Resistor Carbon Resistor Carbon Resistor Carbon Resistor Carbon Resistor Carbon Resistor Carbon Resistor Carbon Resistor Carbon Resistor Carbon Resistor Carbon Resistor Connector Assembly Connector Assembly Connector Assembly Connector Base Post Connector Base Post
9.1K 1/4 F 1.0K 1/4 J 6.2K 1/4 F 10K 1/4 F 10K 1/4 F 1.0K 1/4 J 18.0 1/4 J 10K 1/4 F 1M 1/4 F 18K 1/4 F 1.0K 1/4 J 1M 1/4 F 18K 1/4 F 1.0K 1/4 J 18.0 1/4 J 15K 1/4 F 15K 1/4 F 18.0 1/4 J 9.1K 1/4 F 1.0K 1/4 J 9.1K 1/4 F 6.2K 1/4 F 10K 1/4 F 1.0K 1/4 J 10K 1/4 F 10K 1/4 F 18.0 1/4 J 1M 1/4 F 18K 1/4 F 1.0K 1/4 J 1M 1/4 F 18K 1/4 F 1.0K 1/4 J 18.0 1/4 J 4.7K 1/4 F 2.2K 1/4 F 4.7K 1/4 F 18.0 1/4 J 1.0K 1/4 J 4.7K 1/4 F 4.7K 1/4 J 10.0K 1/4 J 220.0 1/4 J 4.7K 1/4 J 220.0 1/4 J 4.7K 1/4 J 10.0K 1/4 J 220.0 1/4 J 4.7K 1/4 J 220.0 1/4 J 82.0K 1/4 J 1.2K 1/4 J 1.2K 1/4 J 15.0K 1/4 J 22.0K 1/4 J 47.0K 1/4 J 150.0K 1/4 J 10.0K 1/4 J 56.0K 1/4 J 10.0K 1/4 J 100.0K 1/4 J 68.0K 1/4 J 1.2K 1/4 J 56.0K 1/4 J 2.2K 1/4 J AC1 AC2 AC2 M2426XXR 3P SEM2426XXR 4P SE
Connector Base Post Base Post Connector Connector Base Post Fasten Terminal Fasten Terminal Fasten Terminal Fasten Terminal Fasten Terminal Fasten Terminal Fasten Terminal Base Post Connector Connector Base Post Connector Base Post Base PostIC IC IC IC IC XLM Connector XLM Connector Lug Terminal LED LED LED LED LED LED LED Speaker Terminal Lug Terminal Slide Switch Slide Switch Slide Switch Push Switch Rotary Variable Resistor Rotary Variable Resistor Rotary Variable Resistor Rotary Variable Resistor Zener Diode AC Cord AC Cord AC Cord Power Transformer Power Transformer Power Transformer Power Transformer Power Transformer Power Transformer Fan
M2426XXR 5P SEVH- 4P TE M2426XX 7P TETP82223-22 TP82223-22 TP82223-22 TP82223-22 TP82223-22 TP82223-22 TP82223-22 VH- 3P TE M2426XX 5P TEM2426XX 8P TE2P TEM5238AP NJM2068L-D NJM2068L-D NJM7815FA NJM7915FA XLR JACK NC3FAV1-0XLR JACK NC3FAV1-0DT-55-A05W-06 LT032141BAC GR LT311G41BAC RE LT032141BAC GR LT311G41BAC RE LT032141BAC GR LT311G41BAC RE LT311G41BAC RE STB-403AU 4P DT-55-A14W-04 SS001-P223BDB-PA14SS001-P223BDB-PA14SS001-P223BDB-PA14SDDFA3107U-YL UCS C 100K RK12L123C 100K RK12L123A 5K RK11K113A 5K RK11K113MTZ J 5.6B 5.6V UC SJT 3X#18 10A H H05VV-F0.75X3 6ABS H05VV-F 13A KDE2412PMS3-6A/A47
XS350 XS350
OP AMP OP AMP OP AMP REGULATOR REGULATOR INPUT CHANNEL A INPUT CHANNEL B INPUT POWER A. CLIP A. SIG B.CLIP B. SIG PROTECTION PROTECTION SPEAKERS CHANNEL A-2, B-2 SPEAKERS CHANNEL A-1, B-1 FILTER CHANNEL A SWITCH FILTER CHANNEL B SWITCH MODE POWER SWITCH FILTER CHANNEL A FILTER CHANNEL B CHANNEL A CHANNEL B U,V H,W,A B XS350 U,V XS350 H,W,B XS350 A XS250 U,V XS250 H,W,B XS250 A