Philips HTS3520/98, Service Manual

Page: 35 / 63

5-1 Trouble shooting Chart
No display on VFD, and buttons do not work
No display on VFD, and
buttons do not work
Go
Check every supply
voltage on main board is
normal
Yes
Check-24V,+3.3V,+12V
voltage on the power and
front board
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
Check the power key,
open/closed key,source
key is working normaly
Yes
Yes
Yes
Check the front board
signals CS,CLK, Din/out
1.Check whether bad solder
exists on U062 and pins of VFD,
2.Check whether the circuit
connected to S603, S604, S605,
S606, S607, S608,S609 is
broken.
Correct connection
No
Yes
Replace U601 or VFD