2. Troubleshooting flow chart for “Karaoke has no sound”is shown as in the following figure 3.3.2.2:
Analysis: this kind of trouble may adopt signal input method. Test stage bu stage, when a certain
stage does not have disturbance sound in loudspeaker, this stage has trouble; when using this method,
check from back stage to front stage. Another method is signal control method, check stage by stage
from front to back stage, if a stage has no sound, it means that this stage has trouble.
Check signal board
Check
whether C202 has
sound signal
N
Check N210 and MIC
hole circuit
Check
whether R219,
R221 has sound
N
Check PT2315 and CPU
signal P-SCCL, P-DATA
Y
Y
Check
whether C245,
C246 have sound
N
Check N203 and power
supply loop
Y
Check
whether V104,
V105 base electrode
is 0.7AV
N
Check whether V104 or
V105 is stricken through
Check
whether V103
E electrode is high
level
N
Change V103
Y
Whether
MICDET is start
level, and whether KT
is low level
N
CPU, MIC hole and
V200 have trouble
Y
Karaoke has no sound
Figure 3.3.2.2 Troubleshooting flow chart for “Karaoke has no sound”
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