Alesis MIDIVERB IV, Руководство по обслуживанию

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Alesis MidiVerb IV Service Manual‘ 8 03/05/99
8.00 Troubleshooting
This chart is presented in the interest of helping technicians new to our product line. It is
not intended as a substitute for genuine troubleshooting.
Observed Problem Possible Cause Possible Solution
No power, unit is "DEAD". Faulty power supply. Replace and retest.
5V rectifier diode (D2). Test diode, replace if necessary.
Faulty bypass capacitor. Check for burnt or hot capacitors. Replace if
necessary.
Lights up, but no display or function. Faulty 8031. Replace and retest.
Faulty SRAM. Replace, reinitialize memory (Power unit up
while holding "A" and "D") and retest.
Unit "crashed". Reinitialize memory and retest. (Power unit
up while holding "A" and "D")
Faulty M4 ASIC. Replace and retest.
Faulty LCD Module. Test with known good front panel. Replace if
necessary.
Unit locked up (display works but unit
doesn’t function). Loose front panel cable. Reseat cable and retest.
Faulty 8031. Replace and retest.
Garbled LCD display. Unit "crashed". Reinitialize memory and retest. (Power unit
up while holding "A" and "D")
Faulty SRAM. Reinitialize memory and retest. (Power unit
up while holding "A" and "D")
Faulty LCD Module. Test with known good front panel. Replace if
necessary.
Faulty 8031. Replace and retest.
No audio. Faulty M4 ASIC. Replace and retest.
Faulty ADC. Troubleshoot and repair as necessary.
Faulty DAC. Troubleshoot and repair as necessary.
Faulty DIGPOT. Troubleshoot and repair as necessary.
No effects (wet) output. Faulty M4 ASIC. Replace and retest.
Faulty 8031. Replace and retest.
Faulty DIGPOT. Troubleshoot and repair as necessary.
Distorted output. Input levels set too high. Reduce input levels and retest.
Faulty ADC. Troubleshoot and repair as necessary.
Faulty DAC. Troubleshoot and repair as necessary.
Faulty or wrong power supply. Replace and retest.
Power supply circuitry bad. Check regulator outputs and troubleshoot as
necessary.
Faulty op-amp. Troubleshoot and repair as necessary.
Noisy audio. Faulty M4 ASIC. Replace and retest.
Faulty ADC. Troubleshoot and repair as necessary.
Faulty DAC. Troubleshoot and repair as necessary.
No MIDI in. Faulty opto-isolator. Replace and retest.
Faulty 8031. Replace and retest.
No MIDI out. Faulty 8031. Replace and retest.