PC-UM10M
LL-T1815 TROUBLE SHOOTING
4 – 5
THE PC DISPLAY DOES NOT WORK. (DIGITAL DVI)
THE FIRMWARE CANNOT BE UPGRADED
AUDIO DOES NOT SOUND
Does the display work normally with analog inputs?
3
(No)
First, check with analog inputs.
4
(Yes)
Is 14Pin of CN2 at DC+5V?
3
(No)
Check CN2 and the signal source.
4
(Yes)
Are the signal levels of 1PIN, 2PIN, 9PIN, 10PIN,
17PIN, 18PIN, 23PIN, and 24PIN of CN2 changed?
3
(Yes)
IIC8 abnormality
4
(No)
Are the waveforms at 1PIN and 2PIN of IC7
changed normally when the resolution is changed?
3
(No)
Check IC7 peripheral circuits.
4
(Yes)
Check IC7and IC8.
Connected to the analog input CN1?
3
(No)
Connect the jig fro rewriting the firmware to the
analog input CN1.
4
(Yes)
Is SW1 set to 1, 2 side? (CN1 side when viewed
from you)
3
(No)
Set SW1 to 1, 2 side (CN1 side when viewed from
you).
4
(Yes)
Is 2PIN of Q16 at the GND level?
3
(No)
Check SW1 and R258.
4
(Yes)
Are 1PIN and 13PIN of IC6 changed normally?
3
(No)
Check IC6 peripheral circuits.
4
(Yes)
Are signal waveforms provided at 12PIN - 19PIN
of IC18?
3
(No)
ICheck IC18 and IC19 peripheral circuits.
4
(Yes)
Check 31, 32, 33, 35, and 44PIN of IC15. (If there
is no abnormality, IC15 or IC19 is defective.)
Is the audio cable connected to CN2 of the
AUDIO PWB?
3
(No)
Connect the audio cable to CN2 of the AUDIO
PWB.
4
(Yes)
Is 1PIN of CN1 at DC+12V?
3
(No)
Check Q15 of the main PWB and the AU12V
power line.
4
(Yes)
Is the voltage at 2PIN of CN1 changed by varying
the sound volume?
3
(No)
Check IC15 and its peripheral circuits.
4
(Yes)
Are 3PIN and 4PIN of CN1 changed to the GND
level when any display is made?
3
(No)
Check IC20 and its peripheral circuits.
4
(Yes)
Is 5PIN of CN1 at the GND level?
3
(No)
Check CN1, the cable connected to CN1, and
CN3 of the main PWB.
4
(Yes)
Replace the AUDIO PWB.