Sharp XG-MB70X Service Manual page 36

XG-MB70X
Checking the peripheral circuits of the
microprocessor
Are the voltages of approx. 3.3V and 2.5V
applied to both ends of C2030 and C2029
respectively?
YES
Are the oscillations of 133MHz and
64MHz output from pin (3) of X2001 and
pin (3) of X2002 respectively?
YES
Does each terminal of R2039, R2040,
R2042, R2048 and R2050 change?
YES
Do pins (95) and (96) of IC2201 change?
YES
Do pins (74) to (77) and (89) to (94) of
IC2201 change when any key is
operated?
YES
When the power button is pressed, does
the voltage of pin (7) of IC2005 become
3.3V?
YES
Do pulse-shaped waveforms appear at
pins (1), (2), (5) and (6) of IC2005?
YES
Does the voltage of pins (2) and (6) of
IC2006 and pins (3) and (6) of IC2007
change?
YES
Is the voltage of pin (9) of IC3560 5V?
YES
Does the fan rotate?
YES
Go to "Checking the lamp light-up".
NO
Go to "Checking the power supply
system".
NO
Check the peripheral circuits of X2001
and X2002.
NO
Check IC2201 and IC2202. IC2003 is
defective.
NO
Check IC2203. IC2201 is defective. The
I2C bus does not function normally.
NO
IC2201 is defective. The keys do not
function normally.
NO
IC2003 is defective.
NO
IC2005 is defective.
NO
IC2006 or IC2007 is defective.
NO
IC3560 is defective.
Check the power supply circuit or fan
NO
circuit on the main circuit.
36