Calibration—MicroLab
|
Instruction
4.
Set the
120/220
volt
switch on
the
MicroLab
|
power
supply board to
the
120
volt
position.
5.
Adjust
the
oscilloscope to the
following
settings:
@
2
microseconds
per
division
@
50 millivolts per division
@
ac
input
6.
Connect
the
black
lead
of
the voltmeter
to
a
point on
the
aluminum chassis.
7. Connect
the
red lead
of
the voltmeter to the
NEGATIVE
lead
of
capacitor
C5.
Ss
If you
are not using
a digital voltmeter with an
automatic
polarity
feature,
reverse the
placement
of
the
red
and
black
leads.
(The
first
voltage
measured
is
-
12
Vde.)
8.
Turn on
the
variable
ac
power supply.
9.
By
turning
R13
(labeled
-15
ADJ
on
the circuit
board),
adjust the
-12
volt
supply until
the
voltmeter reads
-12.0
volts.
10.
Disconnect
the
voltmeter from capacitor
C5
and
connect the
oscilloscope probe to
C5.
11.
Check
the -12
volt
supply
for not
more
than 50
millivolts
peak-to-peak ripple.
12.
Shut
the variable
power
supply
off.
13. Move
the
HIGH/LOW
switch
to
the
LOW
position.
14.
Adjust
the
variable ac power supply to
108
volts.
15.
Turn on
the
variable
power
supply
and
repeat
steps
9,
10,
and
11.
Do
not
adjust the
-12
volt regulator
at
this
time.
16.
Turn
off
the
variable power supply
and reset the
HIGH/LOW
switch to
HIGH.
17. Reset
the variable
power
supply
to
120
volts
and goon
to
the
+12 volt
adjustment.
This
completes the
-12
volt
adjustment.
6-6
+12
Volt
Adjustment
Perform
the
following
procedure
to
adjust
the
+12 volt
supply.
1.
Place
the
red lead
of
the
voltmeter on
the
positive lead
of
capacitor
C6.
2.
By
turning
R43
(labled
+15 ADJ
on
the circuit
board),
adjust the
power supply until
the
voltmeter reads
+12.0 volts.
3.
Disconnect
the
voltmeter
lead
and
attach
the
oscilloscope probe to
C6.
4. Check for
not more
than
50
millivolts
peak-to-peak
ripple.
This
completes
the
+12 volt
adjustment.
+5
Volt
Adjustment
Perform
the
following
procedure
to
adjust the
+5
volt
supply.
1.
Place
the
red lead
of
the
voltmeter
on
the
positive
lead
of
capacitor
C1
(near
the
+5,
+12,
-12
volt
output
connector).
2.
By
turning
R62,
adjust
the
+5
volt
supply
until
the
voltmeter reads
+5.0
volts.
3.
Disconnect
the
red voltmeter lead
and connect the
oscilloscope probe to
C1.
4.
Check
for
not more
than
50
millivolts
peak-to-peak
ripple.
This
completes the
power supply
adjustment
procedures.
You
may now
reassemble
the
MicroLab
|.
Summary of Contents for 067-0892-00
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