BenQ DV M21, Руководство по обслуживанию

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5.3 Sound failure
z
Check Speaker wires, cold solder, broken or not?
z
Check Speaker impedance, is correct?
z
Test MU1 & MR7, is it around 3.3 V?
z
Test Speaker, is it around 1.9 V rms?
z
Check board to board interconnectors, PCONI & MCON2, is it
improperly joins?
z
Check MJ4 & HR1; is it poor workmanship caused circuit
open or short?
z
Test MCON2 pin16 & pin17 with an oscilloscope, are clock &
data waveform signal normal?
z
Check solder join of the DSP, is it poor workmanship,
cracking open, intermittent? Or DSP fail.
5.4 Firmware Programming failure
z
Test MX1, Mx2 & Mx3 with an oscilloscope, are those clock
waveform signal normal?
z
Test MQ7, MQ8, MQ5, MD2, MD3 & MD5 with an
oscilloscope, are those k waveform signal normal?
z
Test PR10 & PR14; are they 5V & 3.3V respectively?
z
Replace the Flash memory, if fail at programming progress.
z
Check PL9; is it cold solder or open?
z
Try to replace DDR memory, if no fixed by above Flash
replacement.
z
Replace DSP eventually if no memories problems.