JBL ARCSUB-8 Service manual

Page 1
SERVICE MANUAL
SERVICE MANUAL
ARC SUB 8
Discrete Output, High Current
JBL Consumer Products Inc.
250 Crossways Park Drive
Woodbury, N.Y. 11797
A Harman International Company
1112-ARCSUB8 Rev A 10/98
Page 2
Powered Subwoofer ARC SUB 8
This Product is Part of the ARC CINEMA II SYSTEM
TABLE OF CONTENTS
SPECIFICATIONS..........................................................1
WARRANTY ...................................................................2
SAFETY SYMBOLS .......................................................2
CONTROLS AND THEIR FUNCTION...........................3
TEST PROCEDURES....................................................4
TROUBLESHOOTING ...................................................5
ARC SUB 8 AMPLIFIER BLOCK DIAGRAM ................7
CABINET EXPLODED VIEW.........................................8
SPECIFICATIONS
Amplifier Power RMS ...........80Watts @ 1% THD
Drivers ................8"with high-polymer-laminated cone
Inputs ................Line level and High Level
Outputs* ...............High level with High-Pass filter at 180Hz
Crossover Frequency ...........50-150Hz
(continuosly variable)
Frequency Response ...........45Hz to 150Hz
(determined by crossover setting)
Input Impedance .............20kohm
Input Sensitivity .............220mV
ARC SUB 8 ELECTRICAL PARTS LISTS ....................9
ARC SUB 8 MECHANICAL PARTS LISTS ................10
PACKAGING EXPLODED VIEW .................................11
INTEGRATED CIRCUIT DIAGRAM ............................12
PRINTED CIRCUIT BOARD (TOP VIEW) ..................13
SCHEMATIC DIAGRAM 1 ...........................................14
SCHEMATIC DIAGRAM 2 ...........................................15
External Dimensions (Inches)
Height ................9…
Width ................14"
Depth ................12‰
Weight ................18lbs
External Dimensions (mm)
Height ................235mm
Width ................356mm
Depth ................318mm
Weight ................8.1kg
* High-Level (speaker) outputs are active only if high-level input are used.
Occasional refinements may be made to existing products without notice, but will always meet or exceed original specifications unless otherwise stated.
1
Page 3
Powered Subwoofer ARC SUB 8
WARRANTY
This amplifier is warranted against defects in material and workmanship for a period of 90 days from date of shipment, when installed in accordance with the owners manual in a clean, dry, interior home environment. THIS AMPLIFIER IS NOT SUITABLE FOR OPERATION OUTSIDE OR IN HARSH ENVIRONMENTS. During the warranty period, the manufacturer will, at its option, either repair of replace products which prove to be defective.
For warranty service or repair, this product must be properly packed and returned to a service facility designated by the manufacturer. Buyer shall prepay shipping charges to the designated facility and the manufacturer shall pay shipping charges to return the product to buyer. However, Buyer shall pay all shipping charges, duties and taxes for products returned to the manufacturer from another country.
The manufacturer does not warrant that the operation of the product will be uninterrupted or error-free. The Buyer must determine the suitability of the product for his or her purposes.
LIMITATION OF WARRANTY
The foregoing warranty shall not apply to defects resulting from improper or inadequate maintenance by Buyer, Buyer-supplied interfacing, unauthorized modification or misuse, operation
outside of the environment specifications for the product including inadequate ventilation, or improper site preparation, installation, or maintenance.
NO OTHER WARRANTY IS EXPRESSED OR IMPLIED. THE MANUFACTURER SPECIFICALLY DISCLAIMS THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
EXCLUSIVE REMEDIES
THE REMEDIES PROVIDED HEREIN ARE BUYERS SOLE AND EXCLUSIVE REMEDIES. THE MANUFACTURER SHALL NOT BE LIABLE FOR ANY DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES, WHETHER BASED ON CONTRACT, TORT, OR ANY OTHER LEGAL THEORY.
SAFETY SYMBOLS
The following symbols are used throughout this manual and in the product. Familiarize yourself with each of the symbols and its meaning before servicing this amplifier.
Instruction manual symbol. The product will be marked with this symbol when it is necessary for the user to refer to the instruction manual in order to protect the unit against damage.
Indicates dangerous voltages are present. Be
extremely careful.
The CAUTION sign denoted a hazard. It calls
attention to a procedure which, if not correctly performed or adhered to, could result in damage to or
destruction of the amplifier. Do not proceed beyond a CAUTION sign until the indicated conditions are fully understood and met.
The WARNING sign denotes a hazard. It calls attention to a
procedure which, if not correctly performed or adhered to could result in injury or loss of life. Do not proceed beyond a WARNING sign
until the indicated conditions are fully understood and met.
GENERAL SAFETY CONSIDERATIONS
THIS UNIT DOES NOT HAVE A POWER SWITCH; HAZARDOUS VOLTAGES ARE PRESENT WITHIN THE UNIT WHENEVER IT IS PLUGGED IN.
There are voltages and hot components at many points in the amplifier which can, if contacted, cause serious injury. Be
extremely careful. Any adjustments or service procedures that require operation of the amplifier out of its enclosure should be performed only by trained service personnel.
2
Page 4
Powered Subwoofer ARC SUB 8
CONTROLS AND THEIR FUNCTION
1. Output Level - The Output Level adjustment determines volume level strength.
2. Crossover Frequency - The Crossover Frequency adjustment determines the highest frequency the ARC SUB 8 will reproduce. It allows a seamless transition from the subwoofer to the satellite speakers.
3. On (LED) - This LED will light green when the unit is plugged in and is receiving signal. When in standby mode the LED is red.
4. Low Level Input - These left and right Line Level Inputs are normally used when the receiver/processor has line-level pre-amp out  or subwoofer out jacks.
5. High Level Inputs - These High Level Inputs are for receivers that do not have line-level pre-amp out or subwoofer out jacks. When a pair of main or satellite speakers are attached to the OUTPUT terminals, frequencies below 180 Hz are attenuated by the high-pass filter.
3
Page 5
Powered Subwoofer ARC SUB 8
TEST PROCEDURES
General Function
UUT = Unit Under Test
1. Connect both right and left line level inputs (RCA) to signal generator and UUT. Use Y-cable if necessary from mono source. VOLUME control should be full counterclockwise.
2. Turn on generator, adjust to 50mV, 50 Hz.
3. Plug in UUT; red LED should be ON. Turn VOLUME control full clockwise.
4. LED should turn Green; immediate bass response should be 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 either high level input terminal on UUT. Cables should be connected to an integrated amplifier fed by the signal generator.
7. Turn on generator and adjust so that speaker level output is 2.0V, 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 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 3.2 ohms.
3. Connect a pair of speaker cables to driver terminals. Cables should be connected to an integrated amplifier fed by a signal 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 unusual noises.
4
Page 6
Powered Subwoofer ARC SUB 8
CAUTIONS AND WARNINGS
BEFORE THIS AMPLIFIER IS PLUGGED IN, make sure its rated voltage corresponds to the voltage of the AC power source to be employed. Failure to use the correct voltage could cause damage to the amplifier when the AC power cable is plugged in. Do not exceed the rated voltage by more than 10%; operation below 90% will degrade performance or cause the unit to shut off.
1. TROUBLE SHOOTING BEFORE OPENING
Check connections, control settings, driver and other possible external problems. If there is Output, determine if all controls and Inputs function properly. Rotate Pots over full range while applying lateral and vertical oscillating forces to locate possible intermittent function. High Level Inputs should be tested individually both differentially (signal from "-" to "+" with normal output) and in common mode (signal from low level ground to both "+" and "-" shorted together, giving virtually no output). While passing a signal, corner drop the enclosure a few inches to expose possible intermittent problems. Check woofer for rubbing of voice coil or tears in cone or surround. Check cabinet for loose extraneous articles which may have been pushed into front port.
2. REMOVING THE AMPLIFIER.
There are voltages and hot components at many points in the amplifier which can, if contacted, cause personal injury. Be extremely careful. Any adjustments or service procedures that require operation of the amplifier out of its enclosure should be performed only by trained service personnel. Refer to PCB drawings for locations of hazards and familiarize yourself with their locations before starting.
A. Remove the subwoofer grille.
B. Remove the (4) 1 Black PPH screws attaching the
woofer to the cabinet.
C. Remove the woofer, unplug the two connecting
wires.
D. Remove the (8)  screws black pph screws
attaching the ampifier assembly to the cabinet.
E. Remove the ampifier assembly.
F. For access to the input panel, first remove the three
outer screws. Remove knob and nuts from potentiometers. Cut away the sealant securing the cover to the faceplate. The input PCB should now pull out completely.
3. TROUBLE SHOOTING AFTER REMOVAL
Verify AC plug is disconnected. See WARNINGS in section 2.
To prevent loose hardware from reducing safety spacings, it is essential that all hardware be replaced in the same manner as it was removed, with lock washers under all nuts, proper torque on screws and thread locking sealer on the transformer nuts.
If line core or strain relief are replaced, it is necessary to seal them completely to panel with an approved conformal coating to prevent air "whistling" through any openings from woofer pressure.
To reduce the risk or electric shock and/or fire, replace items as marked on schematic with the safety marking only with the exact replacements listed in the safety component list, section 4. If exact replacements are not available, order them from the factory or an authorized service center.
A. Check fuse F1. If blown visually check transformer
for discoloration, and large capacitors (C1, C2) for bulges or venting. Check for shorts with an
Ohmmeter, (see schematic).
B. With ohmmeter, verify voice coil of woofer is
3.2 ohms, and windings of transformer are continuous.
C. Examine board and wiring for obvious damage,
broken or poorly soldered connections, or discoloration.
D. Repair or replace items identified above.
E. For live power testing, attach a 4 ohm 100 watt
resistor to the output wires.
F. If the LED is not on, check for fuse continuity and
then for cold solder joints on CMC1 and bridge diode.
G. With a signal present at the input, the output to the
power amp is at pin #8 of U1. If the signal is not present at pin 8, there is a problem with preamp section. Most likely, a cold solder joint will be the problem. Track back the signal path to locate problem.
5
Page 7
Powered Subwoofer ARC SUB 8
H. If signal present at pin 8, but still no sound, check
for cold solder joints on all power resistors, R4a and R4b and the the power amp module. If C24 is blown, C6 is not soldered or is defective. Check the signal at R2. On the down signal side, the voltage signal should be very small. If signal is similar on both sides of R2, the amp module is likely defective.
I. If you hear a mechanical clicking noise from the amp
module, this indicates that the short circuit protection has been engaged. Check that Q3, Q4 and Q5 are soldered correctly. Also check that Q3 is not shorted to power amp case.
J. If you have to replace the power module, be very,
very patient with the solder removal from this single sided PCB. COMPLETELY REMOVE SOLDER
BEFORE TRYING TO REMOVE THE MODULE!
K. Assembly notes. Top side soldering as below:
J5: solder both ends
J3: solder both ends
J1: solder both ends
R48: solder GND end
At junction of C7a/C7b: Pin to GND
Crossover pot Gnd wire from PDB pad to POT barrel. (Only physical contact required between pot body and faceplate).
Observe all of instrument manufacturer’s instructions and safety warnings in performing this test.
Connect sub-woofer system to a music source. Play at high level while checking for air leaks around panel edge, driver, panel jacks and controls, and voice coil problems such as rubbing or loose turns. With the crossover "frequency" set to 50Hz, very little of the voice content should be heard.
4. REASSEMBLY
Follow all disassembly instructions in reverse order. If the input plate has been removed, it must be re-sealed with a small bead of silicon seal or air leaks may result.
5. LIST OF SAFETY COMPONENTS REQUIRING EXACT REPLACEMENTS
F1 Fuse SLOW BLO 0.5A 250v T type
UL approved
CMC1 mc4438 Neosid 28-52, 2x 2.2mH
#23 awg @ 2x 24
L1 mc4436 Neosid 32-19 200uH
#18SNSR @36
T1 Transformer #4300, Use only factory
replacement
After repair, inspect for possible safety hazards, including loose hardware, missing lock washers, correct fuse and lead dress of primary wires (these must be held in position with cable ties so that they cannot touch secondary components). With ohmmeter, check that panel is connected to signal ground.
It is essential that the following safety insulation test be performed prior to returning the Power Sub-Woofer to the customer, using one of the following methods.
A) Insulation Resistance Test
With a 500VDC Insulation Tester, Check insulation from the outer metal contact of the RCA jack (chassis) to the line neutral of AC
cord. Resistance should be >100M.
B) Hi-Pot Test
If a UL approved Hi-Pot tester is available, test line & neutral of AC cord to outer shell of RCA jack (chassis) at 1100VAC for 2 seconds.
PWR CORD SPT-2 better with polarized plug,
UL appoved wired with the hot side to fused side. Use with UL approved panel strain relief only.
BDR Bridge Rect. 200V 4A Use only factory
replacement.
C1, 2 3300uF, 50V Electrolitic Radial.
Be sure replacement part is at least the same working voltage and capacitance rating. Also the lead spacing is important. Incorrect spacing may cause premature failure due to internal cabinet pressures and vibration.
C6 10u 50V Electrolytic Radial.
R29 4700.25 +-1% Metal
S53AMI Power Amp Module
6
Page 8
Powered Subwoofer ARC SUB 8
ARC SUB 8 AMPLIFIER BLOCK DIAGRAM
7
Page 9
Powered Subwoofer ARC SUB 8
CABINET EXPLODED VIEW
8
Page 10
Powered Subwoofer ARC SUB 8
ARC SUB 8 ELECTRICAL PARTS LISTS
Ref # Part # Description Qty.
Capacitors
C1, 2 30701 3300µF 50V +/-20% 2
ELECTROLYTIC RADIAL
C3 30501 .1µF 50V +/-20% 1
MONO-CERAMIC AXIAL
C4, 5, 9, 17, 24 30502 .1µF 50V +/-20% BIPOLAR 5
MONO-CERAMIC
C6 30705 10µF 50V +/-20% BIPOLAR 1
ELECTROLYTIC RADIAL
C7, 25 30503 .0022µF 50V +/-10% 2
MONO-CERAMIC
C7A, 7B 30505 .1µF 100V +/-20% 2
METAL POLYESTER RADIAL
C8, 10, 14, 18, 30504 .1µF 50V +/-10% 6
19, 20 MONO-CERAMIC
C11 30702 100µF 35V +/-20% 1
ELECTROLYTIC RADIAL
C12 30703 4.7µF 35V +/-20% 1
ELECTROLYTIC RADIAL
C13 30506 .001µF 50V +/-10% 1
MONO-CERAMIC
C15, 16 30704 200.µF 50V +/-20% 2
ELECTROLYTIC RADIAL BIPOLAR
C21 30508 .01µF 50V +/-10% 1
MONO-CERAMIC
C28 30507 .01µF 50V +/-20% 1
MONO-CERAMIC
Diodes
DBR 50100 BRIDGE RECT 200W 4A 1
D1 50101 1N5256B 30V +/-5% 1/2W 1
D3 50102 1N4749A 24V +/-5% 1W 1
D6 50103 1N5234B 6.2V +/-5% 1/2W 1
D7, 8 50104 1N4148 100V +/-5% 0.1A 2
D9, 10 50105 1N4744A 15V +/-5% 1W 2
Resistors
R1 40403 2.2 Meg ohm 1/4W +/-5% 1
CARBON FILM
R2 40408 8.45K1/4W +/-1% 1
METAL FILM
R3 40412 33.2K1/4W +/-1% 1
METAL FILM
R4A, 4B 40105 0.11/2W +/-5% 2 R5, 6, 19 40420 1K1/4W +/-5% 3
CARBON FILM
R7, 21, 44, 45 40409 10K1/4w +/-5% 4
CARBON FILM
R8, 15, 34, 36, 40406 100K1/4W +/-5% 8
38, 42, 43, 57 CARBON FILM
R9 40421 3.9K5W +/-5% 1
3W CAN BE USED
R11, 12 40100 3301/2W +/-5% 2
CARBON FILM
R10, 13 40404 1K2W +/-5% 2
CARBON FILM
Ref # Part # Description Qty.
R14, 20 40405 4.7K1/4W +/-5% 2
R16, 17 40101 8202W +/-5% 2
R18 40407 220K1/4W +/-5% 1
R22 40410 3.3K 1/4W +/-5% 1
R26, 49 40701 1 Meg ohm 1/4W +/-5% 2
R27 40411 24.9K1/4W +/-1% 1
R29 40103 470K1/4W +/-1% 1
R30 40413 274K1/4W +/-1% 1
R31 40414 49.9K1/4W +/-1% 1
R32 40415 470K1/4W +/-5% 1
R35 40416 221K1/4W +/-1% 1
R37 40417 47K1/4W +/-5% 1
R39 40418 22K1/4W +/-5% 1
R40 1-114-154-24 150K1/4W +/-5% 1 R46 40104 4.71/4W +/-5% 1
R48 40419 6.04K1/4W +/-1% 1
R53, 54, 55, 56 40106 1002W +/-5% 4
VR1 40401 100K1/4W +/-10% 1
VR2 40402 5K1/4W +/-10% 1
CARBON FILM
CARBON FILM
CARBON FILM
CARBON FILM
CARBON FILM
METAL FILM
METAL
METAL FILM
METAL FILM
CARBON FILM
METAL FILM
CARBON FILM
CARBON FILM
CARBON FILM
METAL FILM
CARBON FILM
SINGLE LOG POT, FRQ POT
SINGLE LINEAR POT, VOL LEVEL POT
Integrated Circuit
U1 60100 LM324 QUAD OP-AMP +/-15 1
Transistors
Q1 60151 MPS A13 30 NPN(Darl) 1
Q2 60152 2N3906 40 PNP 1
Q3 60153 2N3904 40 NPN 1
Q4, 5 60154 MPS A56 80 PNP 2
Miscellaneous
CMC1 80100 mc4438 Neosid 28-52, 1
L1 80101 mc4436 Neosid 32-19 1
L2 80102 BL02RN2-R62 FERRITE BEAD 2
LED1 50106 DUAL CIR LED (2 LEGGED) 1
T1 80104 TRANSFORMER #4300 1
U2 60301 S53AMI POWER AMP 1
2x2.2mH #23awg @ 2X 24
200uH #18SNSR @ 36
MODULE
9
Page 11
Powered Subwoofer ARC SUB 8
ARC SUB 8 MECHANICAL PARTS LISTS
Item Part # Discription Qty.
SCREWS 70170 #4x0.5 SCREWS TO SECURE INPUT JACKS 2
MACHINE SCREWS 70170 #10x1 BOLTS FOR TRANSFORMER 4
NUTS 70172 #10 KEPS NUTS FOR TRANSFORMER 4
SCREWS 70173 #6x.5 SCREWS FOR FUSE PCB 2
SHIELD A70301 METAL BRACKET MOUNTED ON TRANSFORMER. 1
KNOBS A70302 KNOBS FOR CONTROLS 2
F1 80104 250V, 0.50A, T TYPE SLO BLO FUSE 1
POWER CORD 80105 POWER CORD, 2 CONDUCTOR 1
STRAIN RELIEF 70305 POWER CORD STRAIN RELIEF 1
FUSE PCB 80106 PCB COMPLETE WITH CONNECTORS 1
FACEPLATE 70303 FACEPLATE WITH LABELS 1
COVER A70304 HERMETIC COVER 1
SPEAKER TERMINALS 108115 HIGH LEVEL INPUT AND OUTPUT TERMINALS 1
INPUT JACKS 108320 DUAL RCA INPUT JACKS 1
WOOFER 101500 A8AMI WOOFER 8 1
GRILLE 101810 COMPLETE GRILLE 1
CARTON 101820 SHIPPING CARTON 1
MANUAL 1111-ARCCINII OWNERS MANUAL 1
AMPLIFIER 101850 COMPLETE AMPLIFIER 1
10
Page 12
Powered Subwoofer ARC SUB 8
PACKAGING EXPLODED VIEW
11
Page 13
Powered Subwoofer ARC SUB 8
INTEGRATED CIRCUIT DIAGRAM
12
Page 14
Powered Subwoofer ARC SUB 8
PRINTED CIRCUIT BOARD (TOP VIEW)
13
Page 15
Powered Subwoofer ARC SUB 8
SCHEMATIC DIAGRAM 1
G
F
E
1
2
3
4
5
G
T1
F
E
D
C
B
U2
D
C
S53AMI
B
A
A
1
2
3
4
5
14
Page 16
Powered Subwoofer ARC SUB 8
SCHEMATIC DIAGRAM 2
G
F
E
1
2
3
4
5
G
F
U1c
E
D
C
B
A
U1a
U1d
150K
D
U1b
6.04K
C
100K
2N3906
B
A
1
2
3
4
5
15
Loading...