Epson PX-8 Technical Manual page 241

Press that key and
test continuity be-
tween key switch
contacts.
Test isolation be-
tween key switch
contacts with that key
not depressed.
Possibly a KRTN line
short circuit. Check
insulation between
connector pin 21 or
22 and KRTN lines 0
through 7.
N
N
3.2
Possibly a short cir-
cuit in FPC cable or
printed pattern on cir-
cuit board. Check in-
sulation between all
LED anodes and KSC
lines.
Substitute a known
good key board and
retest.
GOTO
2.5
5-40
y
Inspect solderi ng of
that line and remove
short circuit.
Possibly a trouble on
MAPLE board. Follow
check-out procedures
again to isolate faulty
unit.
REV.-A