This manual is very useful because it presents the technical specifications of the cd player, including the manufacturer of the reader, this helps if you need to replace it. It also displays the settings and layout of the circuit.
Manual was a good representation of service infomation for the EWV404. It worked well for my repair.
Text excerpt from page 39 (click to view)
Main PCBs Trouble Diagnosis
7-1-3. When Control Key does not operate
Check Start
N After turn on the power, does LED turn on red light?
1. Check AC connection 2. Check Power S/W ON 3. Check other PCBs
Y
After ST-BY on Does LED turn on green light?
N
Check the connection of KEY PCB to MAIN PCB -> Check the connection between KEY PCB and MAIN PCB
Y
Is output first pin PW7 normal?
N
1. Replace the CON NECTOR 2. Replace KEY PCB
Y
Check Main PCB
A. First check connection, and then check the output of first pin of PA912(ST-BY 3.3V) B. Check waveform first pin and third pin of PA911. If waveform does not appear, replace connector or KEY PCB. -main TP : RC398, RC399
