Infinity BU-120 Service Manual
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Infinity BU-120 Service Manual

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BU-120/HTS-20
Powered Subwoofer
SERVICE MANUAL
Infinity Systems Inc.
250 Crossways Park Drive
Woodbury, N.Y. 11797
1-800-553-3332
A Harman International Company
Rev G 6 /2001

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  • Page 1 BU-120/HTS-20 Powered Subwoofer SERVICE MANUAL Infinity Systems Inc. 250 Crossways Park Drive Woodbury, N.Y. 11797 1-800-553-3332 A Harman International Company Rev G 6 /2001...

  • Page 2: Safety Information

    BU-120/HTS-20 Amplifier/Subwoofer SAFETY INFORMATION Warning Leakage/Resistance Check Any person performing service of this unit will be exposed to Before returning the unit to the customer, perform a leakage hazardous voltages and the risk of electric shock. It is or resistance test as follows: assumed that any person who removes the amplifier from this Leakage Current.

  • Page 3: Table Of Contents

    BU-120/HTS-20 rev. A PCB (revision 3.53) OPERATION ................11 Solder Side Trace ............23 BU-120/HTS-20 ELECTRICAL PARTS LIST ....24 BU-120/HTS-20 TEST SET UP AND PROCEDURE ....12 BU-120/HTS-20 POWER AMP MODULE BU-120/HTS-20 IC DIAGRAMS ........25 TESTING FLOW CHART ............13 BU-120/HTS-20 SCHEMATIC 1 of 2 ......26 SERVICE BULLETIN INF9902 Rev 1 - FEBRUARY 2001 ..14...

  • Page 4: Detailed Specifications

    BU-120/HTS-20 Amplifier/Subwoofer DETAILED SPECIFICATIONS LINE VOLTAGE Yes/No Hi/Lo Nom. Unit Notes Line US 120vac/60Hz 108-132 Vrms Normal Operation EU 230vac/50-60Hz 207-264 Vrms Normal operation, MOMS required Asia 100vac/50Hz 90-110 Vrms Normal Operation Parameter Specific Unit QA Test Conditions Notes ation...
  • Page 5 BU-120/HTS-20 Amplifier/Subwoofer Limiter (yes/no) Max. Output 150w/10 functional Maximum Output Power Maximum THD as a result -max Power/THD=10% of limiting. Features Phase Switch (yes/no) — functional Volume pot Taper linear — functional (lin/log) Input Configuration — Line In — functional...

  • Page 7: Bu-120/Hts-20 Connections

    BU-120/HTS-20 Amplifier/Subwoofer BU-120/HTS-20 CONNECTIONS When connecting your subwoofer make sure you turn all the power off. There are several ways to connect your subwoofer. Read this section carefully to determine which method is best suited for your installation. The subwoofer may be fed directly with a low-level...
  • Page 8 BU-120/HTS-20 Amplifier/Subwoofer When using a single subwoofer, you MUST use a pair of stereo low-level leads from your preamplifier's outputs. When using two subwoofers, one for the left and another for the right channels, connect the left preamplifier output to BOTH the left and right LOW-LEVEL INPUTS of the subwoofer used for the left channel by using a Female-to-Male “Y”...
  • Page 9 BU-120/HTS-20 Amplifier/Subwoofer Figure 5. - Use this method when using two subwoofers. Figure 6. - Use this method when connecting one subwoofer to satellites. Depending on whether you are using one or two subwoofers, connecting your satellites can be accomplished in one of two ways. If you are using a single subwoofer with a pair of satellites, connect them as shown in Figure 6.
  • Page 10 BU-120/HTS-20 Amplifier/Subwoofer Figure 7. - Use this method when connecting two subwoofers to satellites. If you are using two subwoofers as a stereo pair with a pair of satellites, connect them as shown in Figure 7. BU-120 The subwoofer has a variable frequency...

  • Page 11: Operation

    BU-120/HTS-20 Amplifier/Subwoofer OPERATION Setting the Controls Room Placement 1. Initially set the subwoofer's Volume control to the minimum 8. The room placement of the subwoofer is the most critical aspect of its installation. It will be necessary for you to try position.

  • Page 12: Bu-120/Hts-20 Test Set Up And Procedure

    NOTE: When testing the BU120/HTS-20 amplifier, a load must always be connected to the output terminals, whether the woofer, or a 4 to 8 ohm resistive load.

  • Page 13: Bu-120/Hts-20 Power Amp Module Testing Flow Chart

    BU-120/HTS-20 Amplifier/Subwoofer BU-120/HTS-20 POWER AMP MODULE TESTING FLOW CHART (HTS-20 rev. " A" only)

  • Page 14: Service Bulletin Inf9902 Rev 1 - February 2001

    This is considered a Minor repair All Infinity Service Centers Models: BU-80, BU-120, BU150, HTS-10, HTS-20 Subject: Check Solder Joints in Event of Failure Some performance related complaints in the BU Series powered Subwoofers may be caused by cold solder connections between the 28 pins of the Power Amp Module and the main circuit board.

  • Page 15: Service Bulletin Inf2000-01 Rev2 - February 2001

    In the event you receive a BU80, BU120, HTS-10 or HTS-20 subwoofer with the complaint “no output” and capacitor C6 (10uf 50v NPE) is damaged in the amplifier: Order kit Infinity part# 30722 and replace the following included parts: C6 – (10uf 100v NPE cap) C24 –...

  • Page 16: Tech Tips

    BU-120/HTS-20 Amplifier/Subwoofer TECH TIPS Troubleshooting tips and solutions to common service problems For models: BU-120/HTS-20 TIP# INFTT2000-01 Complaint: How do you replace or service any of the front panel components on the Subwoofer faceplate for model BU-120/HTS-20. Probable Cause: The High level Input terminals, potentiometers, RCA jack, and switch(es) are behind a sealed cover to protect the air-tight integrity of the cabinet enclosure.

  • Page 17: Bu-120/Hts-20 Packing & Cabinet Assembly

    BU-120/HTS-20 Amplifier/Subwoofer BU-120/HTS-20 PACKING & CABINET ASSEMBLY SCREWS (4) SCREWS (8) FEET BU-120/HTS-20 (SET OF 4) CABINET ASSEMBLY #200310 12" WOOFER BU-120/HTS-10 (rev. "A" 200300 HTS-20 (rev. "B") 090-312000-000 CABINET NOT FOR SALE AMPLIFIER TOP STYROFOAM ASSEMBLY RAIL PADS (2 per carton)

  • Page 18: Bu-120/Hts-20 Amplifier Assembly Exploded View

    BU-120/HTS-20 Amplifier/Subwoofer BU-120/HTS-20 AMPLIFIER ASSEMBLY EXPLODED VIEW BU-120/HTS-20 Amplifier Assembly Exploded View BU-120 HTS-20...
  • Page 19 #10 keps nuts for transformer 70173 #6 x 0.5" screws for fuse PCB 70301 Hum Shield Metal bracket mounted on transformer BU-120 and HTS-20 rev "A" ONLY 073-014023-900 Hum Shield Metal bracket mounted on transformer HTS-20 rev "B" ONLY A70302 Volume Control/Crossover Knob BU-120 and HTS-20 rev "A"...

  • Page 20: Component Side Trace

    BU-120/HTS-20 Amplifier/Subwoofer BU-120/HTS-20 rev. A PCB (Component Side Trace)

  • Page 21: Solder Side Trace

    BU-120/HTS-20 Amplifier/Subwoofer BU-120/HTS-20 rev. A PCB (Solder Side Trace)

  • Page 22: Component Side Trace

    BU-120/HTS-20 Amplifier/Subwoofer BU-120/HTS-20 rev. A PCB (Component Side Trace)

  • Page 23: Solder Side Trace

    BU-120/HTS-20 Amplifier/Subwoofer BU-120/HTS-20 rev. A PCB (Solder Side Trace)

  • Page 24: Bu-120/Hts-20 Electrical Parts List

    BU-120/HTS-20 Amplifier/Subwoofer BU-120/HTS-20 rev. A ELECTRICAL PARTS LIST REF# PART# DESCRIPTION REF# PART# DESCRIPTION Resistors 30504 100nF 50V -4% Mono-cer rad 0.2"/ax 0.3" 40705 4.7M 1/4W 5% carbon film 30504 100nF 50V -4% Mono-cer rad 40426 1/4W 5% carbon film 0.2"/ax 0.3"...

  • Page 25: Bu-120/Hts-20 Ic Diagrams

    S53AM/S64AMI - Power Amp module SAFETY PART BU-120 and HTS-20 rev “A” ONLY +6V 15 NOTE: THE FOLLOWING PROCEDURES MUST BE FOLLOWED WHEN INSTALLING NEW AMP MODULES: FAILURE TO FOLLOW ONE OR MORE OF THESE STEPS MAY RESULT IN THE INSTANT DESTRUCTION OF THE MODULE WHEN POWERED UP.

  • Page 26: Bu-120/Hts-20 Schematic 1 Of 2

    BU-120/HTS-20 Amplifier/Subwoofer BU-120/HTS-20 rev "A" SCHEMATIC 1 of 2...
  • Page 27 BU-120/HTS-20 Amplifier/Subwoofer BU-120/HTS-20 rev "A" SCHEMATIC 2 of 2...

  • Page 28: Hts-20 Rev B Electrical Parts List

    HTS-20 (rev B) ELECTRICAL PARTS LIST Part Number Description Ref Designator MAIN PCB Semiconductors 050-002400-100 zener diode 24V HZ-24-2 050-003300-100 zener diode 33V 1N4752 050-006200-100 zener diode PN:HZ6C2/Hit 6.2V 1/2W 050-414802-100 Diode 1N4148 D121,122,123,124 050-524500-200 zener diode P/N:1N4744ARL 15V/1W D3,4 051-101501-000 Transistor pnp 2sa1015gr TO-92 051-181502-000...
  • Page 29 HTS-20 (rev B) ELECTRICAL PARTS LIST (Cont.) Part Number Description Ref Designator 032-100364-300 mylar capacitor 0u1/100V K R C3,4,33,26A 032-220163-300 mylar capacitor 0u0022/100V J C104 032-3300025-300 mylar capacitor 0u0033/50V M C130 032-330263-300 mylar capacitor 0u033/100V J P:5 C119 032-330354-303 mylar capacitor 0u33/63V K P:5 C118 032-470353-303 mylar capacitor 0u47/63V J P:5...
  • Page 30 HTS-20 (rev B) ELECTRICAL PARTS LIST (Cont.) Part Number Description Ref Designator 050-505200-001 LED P/N:LT-2402-25 LED11 062-050800-000 Push Terminal 8P P/N E801 JK101 065-001540-090 P/N15L 1.5x1.8mm 070-560891-108 SCREW BTS-3 2.6x8m/m MODULE-PCB 072-010058-000 RCA JACK 2P P/N:052000W1G (Red,Wht) JK102 072-040032-000 Terminal P:3.96 3P CON3 072-040039-000 Terminal PCB TYPE PC205 (t=0.8mm)T205MA...

  • Page 31: Hts-20 Rev B Circuit Boards

    HTS-20 REV B CIRCUIT BOARDS...
  • Page 32 HTS-20 REV B CIRCUIT BOARDS (cont.)

  • Page 33: Hts-20 Rev B Schematic

    HTS-20 REV B SCHEMATIC...

  • Page 34: Hts-20 Rev B Power Amp Module Schematic

    HTS-20 rev B POWER AMP MODULE U3:A U3:G U3:D 74HC14 10u/50V U3:C U3:B 1N4148 U3:E 1N4148 U3:F IRF530 1N4148 (IRF640) 74HC14 100p 100U/16V R1330K 2N5551 CON1 -15V 100p 1000p U1:B U2:A U2:C LF353 74HC14 U1:A 1N4148 IRF530 LF353 (IRF640) 100p +15V U2:B 74HC14...

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Hts-20

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