Sharp MZ-5500 User Manual

7·1.
8·1.
8·2.
9·1.
9·2.
Check procedure Trouble
phenomenon
Defective location
Check
+5V output voltage. To adjust +5V, use the VR1, Clockwise Ml, VR1, C9, Cl0
turn of V R 1 increases the voltage.
Short current
of +5V is 1 to 2A.
Check
-12V output.
Check that:
+5 V output has a load of 0.2 A.
-12 V output has a load of 0.05 A.
+ 12V output is free load.
While observing the
-12V If the output voltage of -12 V ± 15 % is RC1, 01, 02,01, Rl
output voltage, increase the not seen after raising the input voltage
input voltage. slowly
to 16 VAC.
Check if -12V output
voltage produced.
If no, replace the parts.
If yes, go to next.
Check the.
-12 V output
voltage.
Check ALARM.
Connect
the +5V line to the ALARM pin 08,09,010,07,08,09, C20,
in a manner shown below.
C2l, VR3
0
tIN
C
+5V
1Kn
Then, there should appear +5 V between
OV and ALARM pins.
Increase the input voltage.
When
the input voltage is slowly increased
•
Do not try to manipulate VR5.
to 18 VAC, the voltage on this pin changes
•
Use the memory oscilloscope
Check
if ALARM is +5V.
from OV to +5V (at an input of 15VAC).
when a time setup is used.
If no, replace the parts. It needs to adjust VR5 to attain proper
• Clockwise turn of V R3 makes
If yes, to go END. adjustment of the input voltage, when three a time difference shorter
is a problem. between AC input off a
END
ALARM.
Internal circuit of IC(MB3759)
OUTPUT CONTROL
RT
CT
O.2V
DEAD TIME f0 .
CONTROL ~
NONINV INPUT
INV INPUT
NONINV INPUT
INV INPUT
OSC
FEED BACK 3 ERROR AMP!
-83-
REFERRENCE
REGULATOR

Sharp MZ-5500 Specifications

General

Brand	Sharp
Model	MZ-5500
Category	Desktop
Language	English