Hitachi 61HDX98B Manual page 99

DM-1 TROUBLESHOOTING SYMPTOMS, and ACTIONS
SYMPTOM
Suspected failure of DM-1.
(Power L.E.D. does not blink
twice when AC Power is ap-
plied.) Note: New DM-1 modules
do NOT blink the power LED.
DM-1 boots up OK but TV does
not turn on. (Power LED blinks
twice when AC Power is ap-
plied). Note: New DM-1 modules
do NOT blink the power LED.
Chassis powers on, OSD pre-
sent but no video.
Chassis powers on, but no
OSD. Power LED blinks twice
when AC Power is applied,
(DM-1 is functional).
Note: New DM-1 modules do
NOT blink the power LED.
Video from ATSC/BSS plays
OK, but RF NTSC does not
play.
ACTION
PWR_FAIL must be
>20vdc. Check all power
supplies (+5, +3.3, -5,
+12 & +33VDC) from
PTV to DM-1.
(See drawing) PMQ-2,
PMQ-3
Check communications
activity between DM-1 &
PTV on PMS-2
(See drawing for pin #'s).
1. Check signal sources.
2. Apply ATSC/BSS
signal, check for
"Link Locked LED"
(inside DM-1).
3. If Link LED is on (Link
Locked), check
2H-Y, H&V at PMZ.
(See drawing)
Check 2H-Y, H&V at
PMZ (See drawing). If
signals OK, trouble-
shoot PTV chassis.
1. Check RF NTSC signal
source.
2. Check NTSC
composite video at
PMT-1 (See drawing)
3. Check Sync, Y, R-Y &
B-Y at PMS-2
(See drawing)
(See drawing Page 09-06)
COMMENTS
Power L.E.D. blinks
twice when AC Pwr.
is applied if DM-1
boots up properly.
Note: New DM-1
modules do NOT
blink the power LED.
DM-1 turns on PTV
Chassis.
Functional DM-1 will
generate OSD with-
out a signal source
attached.
A functional DM-1
will always make
OSD if chassis is OK.
Must press button
on remote to see
OSD.
Make sure active
channel selected.
Page 09-07