BBK DV718SI, Service Manual

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Output; check decode board U203 OKR, OKL and there is signal input; test U210 power supply 3.3V
and it is normal; use oscillograph to test three data clock of SACLK, SBCLK, SLRCK that 1389 chip
outputs to U210 and they are normal, so we doubt that the trouble may be caused by U203 or rosin joint;
weld U203 again , test and trouble is removed.
Example 5 Symptom: HDMI has no sound output
Description: HDMI has pivture but no sound, AV is normal
Analysis and troubleshooting: check U701 Mt1392 power supply voltage 1.8V, DV3.3V and they are
normal; check pin 25 reset voltage of U701 and it is 3.3V, which is normal; check 3 audio data outputted
by 1389 chip; ,use oscillograph to test pin 75 of U701 and find SDATA1 has no audio data input; check
1389 chip SDATA1 and there is data output; use resistance level of multimeter to test the line from 1389
chip to U203 and it is not well connected, and a segment of copper line cuts off; after repair the line,
connect and trouble is removed.
Example 6 Symptom: not read CD disc
Description: when reading CD disc, “NO DISC” displays
Analysis and troubleshooting: load CD disc an test; check Q302, pin E voltage is 3.3V, pin B voltage
is 0V, pin c voltage is 3.3V, but, when reading CD disc normally, pin E voltage is 3.14V, pin B voltage is
2.2V, pin C voltage is 2.45V, so we doubt Q302 or circuit around has trouble; take down decode board
and find TC303 of B panel is joint welding; weld again and trouble is removed.
Example 7 Symptom: not read disc
Description: not read CD disc and DVD disc
Analysis and troubleshooting: check laser head and there is laser output, and also focus, trace,
feed and man axis actions, but feed act has abnormality; the normal feed act is to bring laser head to
make small distance movement, but feed range of trouble machine is nearly up to frame terminal, so
firstly check feed circuit, and capacitance of C211 becomes small; after changing capacitor, trouble is
removed.
Example 8 Symptom: surround has no waveform
Description: surround has no waveform output
Analysis and troubleshooting: check pin 1, 7 of U210 and there is waveform output; check Tc248,
Tc249 and they both have waveform output; when checking Q207, Q208, we find that Q207 has rosin
joint; after welding again, trouble is removed.
Example 9 Symptom: disc reading is slow
Description: when reading CD, DVD disc, it is slow.
Analysis and troubleshooting: when checking nerve line and nerve line jack, we find that resistance
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