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 U4s pin 8,9,6 arrive the
condition JP2’3,4,5
Correct connection
Replace U4 or VFD
Yes
Yes
Yes
No
Check-28V,5V,+12V
voltage on the power
and front board
Check the front board
signals SCK,SDA, STB
1.Check whether bad solder exists
on U3 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 CN502 on power board
Trouble shooting chart
4-1
