PC-UM10M
LL-T1820-H/B TROUBLE SHOOTING
4 – 2
2
4
Is the input signal port connected to the analog sig-
nal cable?
3
(No)
IPress the INPUT key to switch to the proper input
signal port.
4
(Yes)
Is DC+12V outputted from CN7 3PIN - 9PIN?
3
(No)
Check the power unit.
4
(Yes)
Is LD60 at DC+5V?
3
(No)
Check the DC+5V power line and IC25 peripheral
circuits.
4
(Yes)
Is LD64 at DC+3.3V?
3
(No)
Check the DC+3.3V power line and IC26 peripheral
circuits.
4
(Yes)
Is LD65 at DC+2.5V?
3
(No)
Check the DC+2.5V power line and IC27 peripheral
circuits.
4
(Yes)
Is the voltage across fuse F1 at DC+12.0V?
3
(No)
Check the POWER_CTL signal and IC24 peripheral
circuits.
4
(Yes)
Is the R156 side of C144 at HIGH level (DC+5V)?
3
(No)
Check the RESET circuit in the peripheral of IC17.
4
(Yes)
Is the FB15 level varied by ON/OFF of SW in the
front?
3
(No)
Check the MAINPW_IN signal and wiring of the main
SW from CN5 - SW PWB.
4
(Yes)
Is the Q6 output (connected to R157) changed to
HIGH level after turning on the main SW and then
to LOW level (DC+0V)?
3
(No)
Check Q6 peripheral circuits.
4
(Yes)
Is 21PIN of IC16 oscillating?
3
(No)
Check IC 16 and the clock circuit in the peripheral of
X2.
4
(Yes)
Is the pin on the C113 side of X1 oscillating?
3
(No)
Check IC18 and the clock circuit in the peripheral of
X1.
4
(Yes)
Are the signal waveforms of LD11 and LD12 (LD5,
LD6) normal?
3
(No)
Check the analog signal cable and CN1 (CN2).
4
(Yes)
Is the signal waveform of LD14 (LD15) normal?
3
(No)
Check IC2 peripheral circuits.
4
(Yes)
Are the signal waveforms of LD18 and LD19 nor-
mal?
3
(No)
Check IC3 and IC4 peripheral circuits.
4
(Yes)
Are the signal waveforms of LD22 and LD23 nor-
mal?
3
(No)
Execute
5
. Check the microcomputer circuit. /
GM5060
4
(Yes)
Are the signal waveforms of LD20 and LD21 nor-
mal?
3
(No)
Remove R96/R97 and check if the signal waveform
on the IC8 side is normal or not.
3
(No)
Replace IC8
(Yes)
4
(Yes)
Check the DCLK
•
DEN line.
Is the signal waveform of RN31 - RN35 normal?
3
(No)
Is the positive (+) side (not installed) of C161 at
DC+3.3V?
3
(No)
Check FB17 and IC28 periph-
eral circuits.
(Yes)
4
(Yes)
Is R246 at HIGH level (DC+3.3V)?
3
(No)
Check IC14 peripheral circuits.
4
(Yes)
Remove the LCD module, and check if the signal
waveform of RN31 - RN35 normal or not.
3
(No)
Check IC23 peripheral circuits.
4
(Yes)