SG 2020 - JBL Audio Service Manual (repair manual)

sg 2020 service manual
Model
SG 2020
Pages
73
Size
4.1 MB
Type
PDF
Document
Service Manual
Brand
Device
Audio
File
sg-2020.pdf
Date

Read JBL SG 2020 Service Manual online

 
Soundgear Series
SG2020   SG3030
3 CD Changer Hi-Fi System
PRELIMINARY
SERVICE MANUAL
JBL Incorporated, Inc.
250 Crossways Park Dr.
Woodbury, New York   11797
CONTENTS
SERVICING PRECAUTIONS . . . . . . . . . . . . . . . .. . . .  . .. . . . . . . . .3
ESD PRECAUTIONS . . . . . . . . . . . . . . . . . . . .
 . . . .
 . ..
 . 
 . . . . . . . . . .5
SPECIFICATIONS . . . . . . . . . . . . . . . . . . . . . . . . 
. . . 
.
  . ..
  . . . . . . . . .6
ADJUSTMENTS . . . . . . . . . . . . . . . . . . . . . . . . . .  .
 . . . .
 . . . . . . . . . .7
TROUBLESHOOTING GUIDE. . . . . . . . . . . . . . . .  . 
. . . .
. . . . . . . . . .9
WAVEFORMS OF MAJOR CHECK POINTS . . . . . . 
. . . .
. . .. . . . . . .14
WIRING DIAGRAM (SG2020). . . . . . . . . . . . . . . . . . . .
 
. . . 
. . . .
. . . . .15
WIRING DIAGRAM (SG3030).  . . . . . . . . . . . . . . . . . . . .
 . . . .
 . . . . . .16
BLOCK DIAGRAM (SG2020) . . . . . . . . . . . . . . . . .  . . . . . . 
. . ..
. . . . .17
BLOCK DIAGRAM (SG3030). .  . . . . . . . . . . . . . . . . . . .  . . 
. . . .
 . . . .18
SCHEMATIC DIAGRAMS  (SG2020/3030). . . . . . . . . . . . . . 
. . .
 . . . .19
PCB BOARDS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 
. . .
. . . . . .35
PACKAGE PARTS LIST (SG2020). . . . . . . . . . . . .  . . . . . . . . . . . . .40
MECHANICAL PARTS LIST (SG2020). . . . . . . . . . .  . . . . . . . . . . . .40
ELECTRICAL PARTS LIST (SG2020). . . . . . . . . . . . . . . . . . . . . . . .43
PACKAGE PARTS LIST (SG3030). . . . . . . . . . . . .  . . . . . . . . . . . . .54
MECHANICAL PARTS LIST (SG3030). . . . . . . . . . .  . . . . . . . . . . . .54
ELECTRICAL PARTS LIST (SG3030). . . . . . . . . . . . . . . . . . . . . . . .57
-3-
SERVICING PRECAUTIONS
NOTES REGARDING HANDLING OF THE PICK-UP
1. Notes for transport and storage
1) The pick-up should always be left in its conductive bag until immediately prior to use.
2) The pick-up should never be subjected to external pressure or impact.
2. Repair notes
1) The pick-up incorporates a strong magnet, and so should never be brought close to magnetic materials.
2) The pick-up should always be handled correctly and carefully, taking care to avoid external pressure and
impact. If it is subjected to strong pressure or impact, the result may be an operational malfunction
and/or damage to the printed-circuit board.
3) Each and every pick-up is already individually adjusted to a high degree of precision, and for that reason
the adjustment point and installation 
screws should absolutely never be touched.
4) Laser beams may damage the eyes!
Absolutely never permit laser beams to enter the eyes!
Also NEVER switch ON the power to the laser output part (lens, etc.) of the pick-up if it is damaged.
5) Cleaning the lens surface
If there is dust on the lens surface, the dust should be cleaned away by using an air bush (such as used
for camera lens). The lens is held by a delicate spring. When cleaning the lens surface, therefore, a cot-
ton swab should be used, taking care not to distort this.
6) Never attempt to disassemble the pick-up.
Spring by excess pressure. If the lens is extremely dirty, apply isopropyl alcohol to the cotton swab. (Do
not use any other liquid cleaners, because they will damage the lens.) Take care not to use too much of
this alcohol on the swab, and do not allow the alcohol to get inside the pick-up.
Storage in conductive bag
NEVER look directly at the laser beam, and don’t let contact
fingers or other exposed skin.
Magnet
How to hold the pick-up
Conductive Sheet
Cotton swab
Pressure
Pressure
Drop impact
-4-
NOTES REGARDING COMPACT DISC PLAYER REPAIRS
1. Preparations
1) Compact disc players incorporate a great many ICs as well as the pick-up (laser diode). These compo-
nents are sensitive to, and easily affected by, static electricity. If such static electricity is high voltage,
components can be damaged, and for that reason components should be handled with care.
2) The pick-up is composed of many optical components and other high-precision components. Care must
be taken, therefore, to avoid repair or storage where the temperature of humidity is high, where strong
magnetism is present, or where there is excessive dust.
2. Notes for repair
1) Before replacing a component part, first disconnect the power supply lead wire from the unit
2) All equipment, measuring instruments and tools must be grounded.
3) The workbench should be covered with a conductive sheet and grounded.
When removing the laser pick-up from its conductive bag, do not place the pick-up on the bag. (This is
because there is the possibility of damage by static electricity.)
4) To prevent AC leakage, the metal part of the soldering iron should be grounded.
5) Workers should be grounded by an armband (1M
)
6) Care should be taken not to permit the laser pick-up to come in contact with clothing, in order to prevent
static electricity changes in the clothing to escape from the armband.
7) The laser beam from the pick-up should NEVER be directly facing the eyes or bare skin.
CLEARING MALFUNCTION
You can reset your unit to initial status if malfunction occur(button malfunction, display, etc.).
Using a pointed good conductor(such as driver), simply short the RESET jump wire on the inside of the
volume knob for more than 3 seconds.
If you reset your unit, you must reenter all its settings(stations, clock, timer)
NOTE: 1. To operate the RESET jump wire, pull the volume rotary knob and release it.
2. If you wish to operate the RESET jump wire, it is necessary to unplug the power cord.
Resistor
(1 Mohm)
VOLUME
UP
DOWN
VOLUME KNOB
RESET jump wire
Conductive
Sheet
Resistor
(1 Mohm)
Armband
Page of 73
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Here you can read online and download JBL SG 2020 Service Manual in PDF. SG 2020 service manual will guide through the process and help you recover, restore, fix, disassemble and repair JBL SG 2020 Audio. Information contained in service manuals typically includes schematics / circuit diagrams, wiring diagrams, block diagrams, printed wiring boards, exploded views, parts list, disassembly / assembly, pcb.