【
】
【
】
【
】
【
】
Example 5
Symptom: power not on
Description: no +5V voltage output
Example 6
Symptom: disc reading is normal but there is no sound output
Description: machine can read disc and output picture normally, but there is still no sound output
Analysis and troubleshooting: use remote controller to restore to default settings firstly, then
connect audio terminal and check whether there is sound output; then switch to 5.1CH, connect audio
terminal and check whether each channel has sound output. Check contact of XS701 and decode board
XS204 and it is good, check 4558 and there is no sound output, test pin 4, 8 of 4558 and find that there
is no +9V voltage, check and find that XS203 +9V has voltage input, test and find that L210 has no
voltage output, after changing L210, trouble is removed.
Example 7
Symptom: not read DVD disc
Description: CD disc reading is normal, after loading DVD disc, it opens automatically
Analysis and troubleshooting: use multimeter to test voltage of Q302 emitter electrode and it is 3.3V,
which is normal, collector voltage is 2.2V, which is normal, test inductor L312 between collector
electrode and pin 23 of XS301 and find that inductor has open circuit, after changing inductor, trouble is
removed.
Example 8
Symptom: not read MP3 disc
Description: DVD disc reading is normal, after loading MP3 disc, it opens automatically, VCD disc
reading is normal
Analysis and troubleshooting: 1. Insert power cord, use multimeter to test whether 220V AC input is
normal ans it is normal;
2. Test whether each voltage input on decode board XS203 is normal and find that+5V has no input,
and others are normal;
3. Unplug flat cable of decode board XS203, test each input voltage again and there is still no +5V
voltage;
4. Check whether two ends of +5V on power supply flat cable from power board CN502 to decode
board is on, and it is normal;
5. Test voltage of two ends of TC506, and +5V has no output, after power off, use multimeter 200
ohm level to test two ends of TC506 and find that resistance is close to aero, so we doubt that
electrolytic capacitor TC506 has electric leakage, take down TC506 and test anode welding pint of
TC506 and find that +5V output is normal;
Conclusion: TC506 has electric leakage, after changing TC506, each output voltage of power board
is normal, insert the power supply flat cable between power board and decode board, power on again
and it is ok, and trouble is removed.
;
- 36 -
Содержание DV725SI
Страница 1: ...service manual DV725SI...
Страница 62: ...21 27M clock signal waveform diagram 22 Reset circuit waveform diagram URST Dv33 58...
Страница 95: ...5 1 7 Surface layer of DECODE SERVO Board 91...
Страница 96: ...5 1 8 Bottom layer of DECODE SERVO Board 92...