SM-SX1/SX1W
– 34 –
TROUBLESHOOTING
No
• Power is not supplied.
Does AC100V stand between Pins 1 and 2 of the power
filter PWB connector CNP502?
(LED904 does not come on and it does not sound.)
• Check the fuse F501.
• Check the parts on the power filter PWB.
• Check the wiring of the inlets SOC501 and CNS501.
Yes
No
Yes
Is any normal voltage output from the power PWB
B1503/CNS503?
• Check the output voltage (OYT terminal) of UNT501 and
UNT502.
• Check the parts (L504 to L511, F502, FS503 and R503 to
R506) on the power PWB.
• Check the 1-bit amplification unit.
(Try to disconnect CNWAM4 and CNWAM3.)
No
Yes
Is 5V supplied to Pin 13 of the microcomputer IC907?
• Check IC306 output.
• Check R391.
No
Is any oscillating waveform found at Pins 14 (OSC2) and
15 (OSC1)?
• Check X900.
• Check IC907.
No
• If no sound is present at the analog or digital input
Yes
Are the speaker relays RLY201 and RLY202 switched?
(when power is supplied and LED904 is lit.)
•
Check whether 12V is supplied to RLY201 and RLY202 or not.
(Check the surroundings of Q201, Q202, R201 to R202.)
• Check whether Q203 and Q204 are on or not.
• Check the line Q203 and Q204 from Pin 41 of the
microcomputer IC907.
Are they properly wired to the 1-bit amplifying unit?
(CNWAM1, CNWAM2, CNWAM3, CNWAM4)
No
Yes
Is voltage properly supplied to 1-bit amplifier? (CNP306)
• Check whether the proper voltage is output from the AC
input filter CNP502 or not.
• Check whether RLY303 is activated or not.
• Check whether Q303 is on or not.
• Check the line Q303 from Pin 42 of the microcomputer
IC907.
No
Yes
Is voltage properly supplied to 1-bit amplifier? (CNP305)
• Check -22V (around Q115 and Q114).
• Check 5V (around Q105 and Q106).
• Check reset 5V.
(Connection from Pin 21 of the microcomputer IC904.)
No
Is any signal output from the connectors CNP303 and
CNP304 for 1-bit amplifier?
• Check CNS601A/B and main volume, VOL601.
• Check the IC107 output voltage which is supplied to drive
the relay.
• Check the relays RLY601 and RLY602 and drive circuit.
Yes
Check the inside of the 1-bit amplifying unit.
To Next Page
Loading...
