Service manual

3.4. Circuit Errors
3.4.1 Power Circuit Failure
OK
NG
Check other circuits.
Confirm the voltage is maintained at approx. +390V between + and -
electrode of C911.
Disconnect the lead connector of CN951 and confirm the output voltage at +215V, +80V, +15V, +8V and
-15V.
Check +5.15V output voltage.
Confirm that the voltage is maintained at approx. +5.15V between the C971
+ electrode and GND.
Remove the load of +5.15V line and check the output voltage of +5.15V.
OK
NG
Voltage is 0V.
The voltage is 2 times as AC input voltage.
Expected failure point
F902, D901, Q901, Q901,
IC902, IC903, D961, D963
D964, D965, D967 or/and D971
Confirm that the voltage is maintained at approx. +18V between + and – electrode of C931.
Expected failure point
IC901and
p
eri
p
heral circuits
NG
OK
Expected failure point
IC903, D932, PC902, D971, IC922, ZD971
Confirm that the voltage is about approx. +18V at Pin 8 of IC901.
NG
OK
OK
NG
Expected failure point
Q902, Q903, PC903 or Q962
After checking above parts.
Check other circuits on the +215V, +80V,
+15V +8V and –15V line.
OK
NG
Confirm the voltage at Pin 7 of CN952 is +5V.
After checking above parts.
*Notice:
When reconnecting, confirm that each power voltage has discharged electricity
.
Expected failure point
IC921 and peripheral circuits, PC901, IC902, D961, D963, D964, D965,
D967 or IC923
OK
NG
Expected failure point
MPU operation (See Item 3.4.8)
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