3-16
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.
4-3. SERIAL FLASH (IC503)
4-3-1. Solution
Please check and replace IC503 on MAIN board.
4-3-2. How to troubleshoot (Countermeasure)
1) If the crystal(X501) does oscillate, check serial flash(IC503) on MAIN board.
Check pin8(VCC), pin6(CLK), pin1(CS#), pin2(DO), pin5(DI) of below waveform.
2) If pin1, 2, 5, 6, 8 doesn’t come out, check damping resistor(R511, R513, R514, R515) of IC503.
If damping resistor of IC503 is OK, then replace IC503. (it need to download program)
3) After change IC503, if It is still not below waveform, check IC501(DSP IC).
4-3-3. Service hint (Any picture / Remark)
VCC
CLK
DO
CS#
< Signal check point >
< Signal waveform >
Содержание CM7420
Страница 13: ...1 12 MEMO ...
Страница 15: ...2 2 MEMO ...
Страница 19: ...A60 4 SPEAKER SECTION FRONT SPEAKER CMS7520F ...
Страница 82: ...3 79 3 80 PRINTED CIRCUIT BOARD DIAGRAMS 1 SMPS P C BOARD TOP VIEW ...
Страница 84: ...3 83 3 84 2 MAIN P C BOARD TOP VIEW ...
Страница 85: ...3 85 3 86 MAIN P C BOARD BOTTOM VIEW ...
Страница 86: ...3 87 3 88 3 FRONT_VFD P C BOARD TOP VIEW BOTTOM VIEW ...
Страница 87: ...3 89 3 90 4 FRONT_MIC PORTABLE P C BOARD TOP VIEW BOTTOM VIEW ...
Страница 88: ...3 91 3 92 5 FRONT_VOLUME P C BOARD TOP VIEW ...
Страница 89: ...3 93 3 94 FRONT_VOLUME P C BOARD BOTTOM VIEW ...