DOWNLOAD JBL SG 2020 Service Manual ↓ Size: 4.1 MB | Pages: 73 in PDF or view online for FREE

Model
SG 2020
Pages
73
Size
4.1 MB
Type
PDF
Document
Service Manual
Brand
Device
Audio
File
sg-2020.pdf
Date
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JBL SG 2020 Service Manual ▷ View online

-9-
TROUBLESHOOTING GUIDE
Turn power on.
Is power on?
Does initial read work?
Does it play?
Does it output audio?
Check power supply circuit.
(Check PN 807)
Check laser circuit.
Check focus circuit.
Check disc.
Check tracking servo circuit.
Check audio circuit.
OK
YES
YES
YES
YES
NO
NO
NO
NO
Fails to initial read
-10-
1.3V
A
B
YES
YES
YES
YES
YES
YES
YES
YES
NO
NO
NO
NO
NO
NO
NO
NO
NO
NO
Does laser light?
Disc motor turns.
Does RF
waveform
appear?
TP 801(RF)
Does tracking
servo work?
Lower envelope
of TP801(RF)
waveform is flat.
Does signal
appear at
TP801(TEO)?
Does signal appear at IC 803
Pin      and Pin     ?
Does GFS (IC802 pin 
)
show as below?
Is rotation normal?
Is there no dropout of RF
signal?
Does TE2 signal
appear at pin
53
of IC801?
Defective IC
801, pick up
and/or open
wire.
Detective pattern.
Defective IC 801
and/or IC 803
Defective pick-up
and/or connector.
Defective IC 801.
Scratch in disc
initial read area.
Defective pick-up
adjustment focus offset.
26
27
25
-11-
A
NO
NO
NO
NO
NO
NO
Laser does not light.
Is “3.5V” applied to pin      of IC 801?
Is power supplied to laser Q801?
(Q 801 collector: about 1.8V)
Does laser current flow?
1.0V across R801
Is data transferred from
MICOM IC ?
Does voltage appear at IC
803 pin 
, 
?
Defective MICOM.
Defective MICOM.
Defective connector.
Defective IC 801, 803 
Defective slide motor and/or
connector.
Defective LMT SW and/or
connector.
Defective Q 801 and/or laser.
Defective laser and/or
connector.
Did pickup return to
innermost circular?
Does it stop at inner pick
circular after shift?
Is defect output from LM
SW applied to pin 
of
PN803?
R801
1.0V
R801
1.0V
YES
YES
YES
YES
OPEN
CLOSE
YES
YES
YES
YES
YES
YES
70
11
12
2
-12-
B
C
Does lens move up/down?
Does IC 801 out focus
search signal?
IC 801 pin     (FEO)
Is focus search signal
applied to pin     ,     of
CN801?
Laser lights.
Confirm
initial
read with
disc
Defective IC801 
Defective IC803 
Defective IC 801.
Open activator and/or
connector.
Open connector and/or
defective IC 801.
Incorrect turntable height.
Degraded laser diode.
Does TP 801 RF signal appear even in
low level?
Is laser output adjustment correct?
Does FOK(focus ok) signal appear?
YES
YES
YES
YES
YES
YES
TP801
(RF)
IC801 pin  
(FOK)
NO
NO
NO
NO
NO
NO
48
13
16
40
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