3-5
Copyright © 2018 LG Electronics Inc. All rights reserved.
Only for training and service purposes.
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 VFD301 on FRONT board.
3-1-2. How to troubleshoot (Countermeasure)
1) Check if 12 VA is output from SMPS to VFD via the MAIN board.
2) Check if Check if VFD_5 V, DVCC_3 V to CN304 is normal.
3) Check if IC500 outputs VFD_DAT, VFD_CLK and VFD_STB to the FRONT board.
4) Check if VFD301 output SW signal to the FRONT board.
If the SW signal isn’t output, replace VFD301 with new one.
5) check if Q300 and Q301 to the FRONT board.
If the VH signal isn’t output, replace Q301, Q302 with new one.
If the VH signal is output, replace VFD301 with new one.
3-1-3. Service hint (Any picture / Remark)
< Waveform of GR and SG signal >
Содержание CK57
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