No Display On Vfd, And Buttons Do Not Work; Trouble Shooting Chart - Philips HTS3520/12/05 Service Manual

No display on VFD, and buttons do not work

No display on VFD, and
buttons do not work
Go
Check every
voltage on main board is
normal
Yes
Check-24V,+3.3V,+12V
voltage on the power and
front board
Yes
Check the power key,
open/closed key,source
key is working normaly
Yes
Check the front board
signals CS,CLK, Din/out
Yes
1.Check whether bad solder
exists on U062 and pins of VFD,
2.Check whether
connected to S603, S604, S605,
S606, S607,
broken.
Yes
Replace U601 or VFD
supply
the circuit
S608,S609 is
5-1
No
Refer to Power supply board part
No
Fix the connection XS601 on front
board and XP9 on main board
No
Replace U24 on main board,or replace
the main board
No
Check the U601 pin 6 7,8,9 arrive the
condition XS601 6,9,7
No
Correct connection

Trouble shooting Chart