Text preview for : 360TROUBLE.pdf part of LG 360TROUBLE LG Audio FFH-360 360TROUBLE.pdf
Back to : 360TROUBLE.pdf | Home
TROUBLESHOOTING GUIDE
Turn power on.
NO Check power supply circuit.
Is power on? (Check PN 813)
YES
NO
Does initial read work? Check laser circuit.
YES
Check focus circuit.
Check disc.
NO
Does it play? Check tracking servo circuit.
YES
NO
Does it output audio? Check audio circuit.
YES
OK
-9-
Fails to initial read
NO
Disc motor turns. NO Does laser light? A
YES
YES B
Does RF Does tracking Does signal Does TE2 signal
NO NO NO NO
waveform servo work? appear at appear at pin 53 Defective IC
appear? Lower envelope TP801(TEO)? of IC801? 801, pick up
TP 801(RF) of TP801(RF) and/or open
waveform is flat. wire.
1.3V
YES YES
YES Detective pattern.
Does signal appear at IC 803
Pin 26 and Pin 27 ? NO Defective IC 801
and/or IC 803
YES Defective pick-up
and/or connector.
Is rotation normal? NO Does GFS (IC802 pin 25 ) NO
show as below? Defective IC 801.
YES
Is there no dropout of RF Scratch in disc
NO
signal? initial read area.
Defective pick-up
YES adjustment focus offset.
- 10 -
A Laser does not light.
Is "3.5V" applied to pin of IC 801?
YES NO
NO NO
Did pickup return to Is data transferred from Defective MICOM.
innermost circular? MICOM IC ?
YES YES
Does voltage appear at IC NO
803 pin , ? Defective IC 801, 803
YES Defective slide motor and/or
connector.
Does it stop at inner pick Is defect output from LM
circular after shift? SW applied to pin of
YES PN803? NO Defective LMT SW and/or
connector.
OPEN CLOSE
YES Defective MICOM.
YES
NO
Is power supplied to laser Q801? Defective connector.
(Q 801 collector: about 1.8V)
R844 1.0V YES
YES Defective Q 801 and/or laser.
Does laser current flow?
YES Defective laser and/or
1.0V across R801 R844 1.0V
connector.
- 11 -
B Laser lights.
NO Does IC 801 out focus NO
Does lens move up/down? search signal? Defective IC801
YES
IC 801 pin (FEO)
YES
Is focus search signal
applied to pin , of NO
CN801? Defective IC803
Open activator and/or
YES connector.
Confirm Does TP 801 RF signal appear even in
initial low level?
read with
disc NO Open connector and/or
defective IC 801.
YES
Is laser output adjustment correct?
NO Incorrect turntable height.
Degraded laser diode.
YES
Does FOK(focus ok) signal appear?
NO
Defective IC 801.
TP801
(RF)
IC801 pin
(FOK)
YES
C
- 12 -
C
YES
Does FE1 signal appear? IC 801 59 pin
NO Defective IC 801.
Open pick diode
YES
Does FZC signal (focus zero cross signal)
appear at pin 30 of IC 801, ISTAT (SENSE) (Focus servo turns
terminal? NO Defective IC 801. ON by FZC signal
of FOK mod.)
FER
ISTAT(SENSE)
YES
Does SMON signal appear
at pin 73 of IC 802? NO Defective Pattern between IC 801 and
IC 802.
Does SMPO signal appear
at pin 75 of IC 802?
YES
Is drive voltage applied to disk motor?
NO Defective IC 801, 803 and/or
peripheral circuit.
Start mode
YES
Defective disk motor and/or insulation.
- 13 -
WAVEFORMS OF MAJOR CHECK POINT
1. HF signal (RF signal ) waveform 2. EFM signal (pin 31 IC 801)waveform
(Test Point TP801) during normal play during Normal Play
0.5V/Div.
500nS/Div.
2V/Div.
500nS/Div.
OV OV
3. Focus coil drive waveform(Pin NO , of IC 803)