Section 2 Electrical; Electrical Troubleshooting Guide & Waveforms; Main, Front & Tuner Part; System Control - LG LAC6700R Service Manual

ELECTRICAL TROUBLESHOOTING GUIDE & WAVEFORMS
1. MAIN, FRONT & TUNER PART
No Symptom
1 No Power
2 Not available Remocon
3 Not available to Volume control
4 Not available to Key Control
5 No sound
* Power IC
: Refer to next page
6 No Line out signal
8 Heard Pop Noise
9 Not avaliable to Telephone Mute
10 Not avaliable to ANT(Motor Type) Control Checked the ANT Control.
11 Not avaliable to Remote
(External AMP)
12 No output Beep sound.
Copyright © 2007 LG Electronics. Inc. All right reserved.
Only for training and service purposes

SECTION 2 ELECTRICAL

Check Point

SYSTEM CONTROL

Checked the Fuse.
Checked the Back up Vdd, Gnd.
Checked the Micom Back Up Vdd.
Checked the Micom Ground.
Checked the Reset.
Checked the X-tal.
Checked the ACC in.
Checked the detachable switch.
Checked the flipdown Detector.
Checked the Key line.
Checked the Remocon Sens Vdd.
Checked the Remocon Sens line.
Checked the Encoder Volume.
Checked Tact switch.
Checked Key line.
Checked the E-VR Vdd.
Checked the E-VR Ground.
Checked the E-VR control.
Checked the E-VR Signal in/out.
Checked the E-VR Mute Control
Checked the Power IC Vdd.
Checked the Power IC Ground.
Checked the Power IC Control.
Checked the Power IC Signal in/out.
Checked the Power IC Mute.
Checked the Power IC Standby.
Checked the Power IC Ripple.
Checked the Main Connector.
Checked the E-VR Vdd.
Checked the E-VR Ground.
Checked the E-VR control.
Checked the E-VR Signal in/out.
Checked the OPAMP Vdd.
Checked the OPAMP Ground.
Checked the OPAMP Signal in/out
Checked the Line out Mute circuit
Check the Line out Jack
Checked the Mute Control.
Checked the AF Mute.
Checked the telephone Mute Control.
Checked the Mute Control.
Checked the Remote control.
Checked the Beep Control.
CN801
CN801(16, 15)
IC301(14),D307, IC401(30,47,50,99,100)
IC401(20,51,97,98)
IC402. IC401(90)
X401, X402
Q301,Q302, IC401(38), CN801(14)
SW401, IC401(73)
CN901(19), IC401(74)
IC401(52,53)
CN901(14),Q316,Q317,D307
RM901, IC401(5)
SW901, IC401(40,41)
SW902 ~ SW918
IC410(52,53)
IC301(10),IC601(24)
IC601(15)
IC601(22,23), IC401(1,2)
IC601(5,6,7,8,9,10,11,13)
IC601(17,18,19,20)
IC601(21), IC401(6)
IC801(6, 20)
IC801(1, 2, 8, 13, 18, 24)
IC801(4, 22), IC401(3,10)
IC801(11,12, 14, 15)
IC801(3,5,7,9,17,19,21,23)
IC801(22)
IC801(4)
IC801(10)
CN801(1,2, 3, 4, 8, 9, 12, 13)
IC301(10),IC601(24)
IC601(15)
IC601(22,23), IC401(1,2)
IC601(5,6,7,8,9,10,11,13)
IC601(17,18,19,20)
IC701(8),IC702(8)
IC701(4),IC702(4)
IC701(3,5,7,1)
IC702(3,5,7,1)
Q705,IC401(48)
CN703
IC601(21), IC801(4, 22), IC401(3,6,10)
TU101(19), IC401(4)
CN801(5), Q305,Q306, IC401(62)
IC601(21), IC801(4, 22), IC401(3,6,10)
IC301(12,13),IC401(87)
CN801(6), IC402(1,2,4),Q308,Q309
IC401(63,64)
IC401(80), BU301
2-1
Location No.
LGE Internal Use Only