
3-9
ONE POINT REPAIR GUIDE
NO BOOTING IN CD/USB FUNCTION
After you turn on power key and displayed message in the following order
(HELLO --> VOL XX --> CD or USB) on VFD,
it will not display other message on VFD, and it will not boot-up normally.
4-4. SDRAM (IC502)
4-4-1. Solution
Please check and replace IC502 on MAIN board.
4-4-2. How to troubleshoot (Countermeasure)
1) Check below waveform & soldering status of SDRAM (IC502) on MAIN board.
If pin17(#CAS), pin18(#RAS), pin19(#CS), pin38(CLK), pin29(address), pin2(DQ) doesn’t come out,
check damping resistor (R568, R506, R570, R544, R547).
2) If resistor is OK, then replace IC502 (SDRAM).
3) After change IC502, if it is still not below waveform, check IC501 (DSP IC).
4-4-3. Service hint (Any picture / Remark)
V CC
Re set
a ddress
da ta
/ CS
R AS
/ W E
C AS
IC502
< Signal check point >
< Signal waveform >
Summary of Contents for CM9550
Page 15: ...2 2 ...
Page 20: ...LED SUB LED MAIN A60R A61 A62 651 652 FRONT SPEAKER NS9550F RIGHT SPEAKER ...
Page 21: ...LED SUB LED MAIN A91 A90 952 952 A92 951 4 2 SUBWOOFER SPEAKER NS9550W ...
Page 61: ...3 40 ...
Page 81: ...3 79 3 80 3 MAIN P C BOARD TOP VIEW ...
Page 82: ...3 81 3 82 4 MAIN P C BOARD BOTTOM VIEW ...
Page 83: ...3 83 3 84 5 FRONT VOLUME MIC PORTABLE P C BOARD TOP VIEW ...
Page 84: ...3 85 3 86 6 FRONT VOLUME MIC PORTABLE P C BOARD BOTTOM VIEW ...