Hitachi RAS-50WX8 Service Manual page 151

LD301 blinks 9 times.
Communication error.
Is 35V DC being output at No
teminals C and D?(Normally,
33-38.5V DC is output.)
Yes
Interface relay
V
V
Coil terminal
Contact terminal
No
Is 35V DC being output across R914?
Yes
Is 12V DC being supplied across
No
the control side (coil terminal) of
interface relay?
Yes
Yes
Is a voltage (at least 10V)being
generated between the contact
terminals of interface relay?
No
Check the interface curcuit.
D907 and C910 may be defective.
There is defective section between the
12V output of switching power supply on
the main P.W.B. and interface relay (also,
check for contact with solder, etc.).
Replace the interface relay.