LG MCV1306 Service Manual

3-14
ONE POINT REPAIR GUIDE
3. VFD IS NOT DISPLAYED WHEN POWER ON THE SET
When power on the set, any icons or characters on VFD are not displayed.
3-1. VFD
3-1-1. Solution
Please check and replace DIG301 on FRONT board.
3-1-2. How to troubleshoot (Countermeasure)
1) Check if 32 V, FL+ and FL- are output from SMPS to VFD via the MAIN board.
2) Check if the IC101 outputs VFD_RST, VFD_CLK, VFD_STB, and VFD_STB to the FRONT board.
3) Check if the VFD grid current amplifier circuit (Q301, Q303, Q304) on the FRONT board.
Check the drive signal to the transistor’s base.
 If the control signals from VFD (TP302, TP303, TP304) isn’t output, replace VFD with a new one.
 If the transistor doesn’t work, replace it.
3-1-3. Service hint (Any picture / Remark)
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j  G GSG G GGG
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< Waveform of the grid current driver >

LG MCV1306 Specifications

General

Speaker type	-
RMS rated power	1380 W
Subwoofer driver diameter (imperial)	10 \
Cassette deck	No
Product color	Black
Disc loading type	Tray
Optical disc player	Yes
Number of optical discs	3 discs
Recording on	USB
Audio formats supported	MP3
Apple docking compatibility	iPod
Volume control	Rotary
Power source	AC