No display on VFD, and buttons do Not work
No
No
No
Yes
Yes
No display on VFD, and
buttons do Not work
Check every supply
voltage on main board is
Normal
Refer to Power supply board part
Check the main board U107’s pin
AE4,AD5,AE5 arrive the front
board U4’s pin 6,8,9 connect
condition
Correct connection
Replace U4 or VFD
Yes
Yes
Yes
No
C12V,-12V
voltage on the power
and front board
Check the front board
signalsVSTB
ˈ
VCLK, VD
1.Check whether bad solder exists
on the front board U4 and pins of
VFD
2.Check whether the circuit
connected to K1, K2, K3, K4, K5,
K6 is broken.
Fix the connection JP1 on front board
and CN504 on power board
Trouble shooting chart
5-1