JBL-SUB125-sub-sm 电路图 维修手册.pdf
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1、JBL Consumer Products Inc. 250 Crossways Park Drive Woodbury, N.Y. 11797 A Harman International Company Rev B 7/2003 SUB125/125a Amplifier/Subwoofer SERVICE MANUAL RadioFans.CN 收音机爱 好者资料库 2 Amplifier/SubwooferSUB125 GENERAL SPECIFICATIONS SCS125/125a System Frequency Response 35Hz 20kHz (6dB) SUB125
2、 Amplifier . . 75 watts RMS Bass. . . . . 8 woofer, bass-reflex enclosure Dimensions (H x W x D) 14-1/8 x 13 x 13 inches 359 x 330 x 330mm Weight . . . 27.5 lbs/12.5 kg Refinements may be made on occasion to existing products without notice, but will always meet or exceed original specifications unl
3、ess otherwise stated. TABLE OF CONTENTS COVER.1 GENERAL SPECIFICATIONS.2 TABLE OF CONTENTS.2 SCS125/125a SPECIFICATIONS.3 CONTROLS AND THEIR FUNCTION.5 SCS125/125a SPEAKER LEVEL CONNECTIONS .6 SCS125/125a LINE LEVEL CONNECTIONS .7 SUB125 TEST SET UP AND PROCEDURE.8 SIMPLE TROUBLESHOOTING.9 Service B
4、ulletin JBL9901 .10 SCS125/125a PACKING.11 SUB125 EXPLODED VIEW.12 SUB125 PCB COMPONENT SIDE.13 SUB125 PCB SOLDER SIDE.14 SUB125 ELECTRICAL PARTS LIST .15 SUB125 INTEGRATED CIRCUIT DIAGRAMS.17 SUB125 POWER AMP SCHEMATIC DIAGRAM.18 SUB125 PRE-AMP SCHEMATIC DIAGRAM.19 The SUB125 is part of the SCS125/
5、125a system RadioFans.CN 收音机爱 好者资料库 SCS125/125a SPECIFICATIONS LINE VOLTAGEYes/NoHi/Lo LineUnitNotes US 120vac/60HzYes108-132VrmsNormal Operation EU 230vac/50-60HzYes207-264VrmsNormal operation, MOMS required Asia 100vac/50HzYes90-110VrmsNormal Operation Spec.UnitLimitsConditionsNotes Amp Section Ty
6、pe (Class AB, D, other)ABABn/aSink required for Class AB Load Impedance (speaker)4Ohmsn/aNominalZ-curve required Rated Output Power80Watts801 input driven THD Rated Power0.08%0.322k filter THD 1 Watt0.1%0.522k filter DC Offset10mV-DC20 Speaker Outputs Damping factor200DFn/a Input Sensitivity Input F
7、requency50Hz50Nominal Freq.1 input driven Line Input220mVrms2dBTo Rated Power1 input driven Speaker/Hi Level Input4.26Vrms2dBTo Rated Power(-26dB below Line In).1 input driven Signal to Noise SNR-A-Weighted100dBA90rel. to rated powerA-Weighting filter SNR-unweighted80dBr60rel. to rated power22k filt
8、er SNR 1W-unweighted60dBr55rel. to 1W Output22k filter Residual Noise Floor1.5mVrms2.5Volume max, using RMS reading DMM/VOM (or A/P) Residual Noise Floor1mVrms(max)2Volume max, w/ A/P Swept Bandpass Measurement (Line freq.+ harmonics) Input Impedance Line Input15Kohmsn/aNominal Speaker/Hi Level Inpu
9、t4.7Kohmsn/aNominal Filters Low Pass (fixed or variable) fixed Low Pass filter (point or range) 135Hz2dB-3dB Point Slope24dB/Octaven/a Q1.8Dampingn/a2 cascaded 2nd order filters of 1.8 red LED should be ON. Turn VOLUME control full clockwise. 4.LED should turn Green; immediate bass response should b
10、e heard and felt from port tube opening. 5.Turn off generator, turn VOLUME control fully counterclockwise, disconnect RCA cables. 6.Connect one pair of speaker cables to both high level input terminals on UUT. Cables should be connected to an integrated amplifier fed by the signal generator. 7.Turn
11、on generator and adjust so that speaker level output is 3.0V, 50 Hz. Turn VOLUME control full clockwise. 8.Green LED should light, immediate bass response should be heard and felt from the port tube opening. Sweep Function 1.Follow steps 1-4 above, using a sweep generator as a signal source. 2.Sweep
12、 generator from 20Hz to 300Hz. Listen to the cabinet and drivers for any rattles, clicks, buzzes or any other noises. If any unusual noises are heard, remove driver and test. Driver Function 1.Remove driver from cabinet; detach + and - wire clips. 2.Check DC resistance of driver; it should be 3.3 oh
13、ms. 3.Connect a pair of speaker cables to driver terminals. Cables should be connected to an integrated amplifier fed by a signal generator. Turn on generator and adjust so that speaker level output is 5.0V. 4. Sweep generator from 20Hz to 1kHz. Listen to driver for any rubbing, buzzing, or other un
14、usual noises. 9 Amplifier/SubwooferSUB125 SIMPLE TROUBLESHOOTING If there is no sound from any of the speakers, check the following: Receiver/amplifier is on and a source is playing. Powered subwoofer is plugged in and is either in the “On” or “Auto” position. Check all wires and connections between
15、 receiver/ amplifier and speakers. Make sure all wires are connected. Make sure none of the speaker wires are frayed, cut or punctured. Review proper operation of your receiver/amplifier. If there is no sound coming from one speaker, check the following: Check the “Balance” control on your receiver/
16、amplifier. If the system plays at low volumes but shuts off as volume is increased, check the following: Check all wires and con-nections between receiver/ amplifier and speakers. Make sure all wires are connected. Make sure none of the speaker wires are frayed, cut or punctured. If more than one pa
17、ir of main speakers is being used, check the minimum impedance requirements of your receiver/amplifier. If there is low bass output, check the following: Make sure the connections to the left and right “Speaker Inputs” have the correct polarity (+ and ). Powered subwoofer is plugged in and is either
18、 in the “On” or “Auto” position. If there is no sound from the surround speakers, check the following: Check all wires and connections between receiver/ amplifier and speakers. Make sure all wires are connected. Make sure none of the speaker wires are frayed, cut or punctured. Review proper operatio
19、n of your receiver/amplifier and its surround sound features. Receiver mode must be in Dolby Pro logic, Dolby Digital, or any other mode that creates a surround-sound effect. Even under normal operation, when viewing movies and television, surround sound is not present at all times at a high volume
20、- only when the program has chosen to send information there. Service Bulletin JBL9901 To: All JBL Service Centers - January 1999 This is considered a Minor repair Model: Sub125 (SCS125 Powered Subwoofer) Subject:Amplifier plate overheating; Blown fuses In the event you receive a Sub125 (SCS125 Powe
21、red Subwoofer) with the complaint “amplifier plate is getting too hot”, or “the unit is blowing fuses”, perform the necessary steps listed below to change the bias current of the amplifier. This procedure should be performed on all Sub125 amplifiers being serviced for any reason: 1.Set the subwoofer
22、 cabinet on a padded surface with amplifier facing upwards. 2.Remove the (14) Philips screws holding the amplifier and inner plastic cover to the cabinet. Four of these 14 screws are in each corner, slightly larger and just inside the smaller corner screws. 3.Remove amplifier assembly carefully . Do
23、 not pull the amplifier out of the cabinet too much; it can disconnect the speaker wires. (The amp assembly can be laid on one corner of the cabinet for the remainder of the procedure without disconnecting the speaker wires). 4.Carefully pry plastic cover off amplifier assembly. If you are too aggre
24、ssive Molex connector P104 may be damaged; speaker wire inside the cover has little extra length. Lift the left side of the cover first to avoid disconnecting the cable at P104; this connector is located on the right side of the plate inside the cover. 5.Once the cover is pulled back, locate VR101.
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