HP Lab Series - Adjustment and Calibration Steps

Table
5-7.
Selected
Semiconductor
Chari!cteristics
(Continued),
REFERENCE
~PART
NO.
SUGGESTED
DESIGNATOR
CHARACTERISTICS
REPIACEMENT
CR2-5, CR9-15,
Si.
rectifier,
200mA
180prv
1901-0033
1N485-B
Sylvania
CR17, CR18
CR7
Si.
diode,
iov,
400mW
1901-0460
1N4830
G.E.
CRB,
CR16
Si.
rectifier,
400mW,
lOprv
1901-0461
1N4828
G.E,
VR3
Zener
diode,
40.2V,
l.SW
1902-0431
1N3803
Motorola
VR4
Zener
diode,
16.2v; 400mW
1902-0184
1N966
Motorola
VR5
Zener
diode,
4.
22V,
400mW
1902-3070
lN749
Motorola
Table
5-8.
Checks
and Adjustments After Replacement
of
Semiconductor
Devices
REFERENCE
FUNCTION
CHECK
ADJUST
Ql
Constant
voltage
differ•
Constant
voltage
(CV)
line
and
load
regu-
R6
or
RB
ential
amplifier.
lation.
Zero Volt
output.
Q2
Constant
current
differ-
Constant
cur.rent (CC)
line
and
load
regu-
R25oi."R2B
ential
amplifier.
laUon.
Zero
current
output.
Q3,Q4
Mixer
and
error
amplifier.
CV
/CC
load
regulation.
CV
transient
re-
R30
sponse.
Q6
Series
regulator.
CV
/CC
load
regulation.
Q8,Q9
Reference
regulator.
Reference
circuit
line
regulation.
R26
QlO
Clamp
circuit.
CC
load
regulation.
Qll-15
Meter
circuit.
Meter
zero.
Valtmeter
I
a~eter
.tracking.
R63,R7Z,
R5.6,R38
Ql8,Ql9
SCR
control
amplifiers~
Voltage
across
Q6.
R99
CR1,CR2
Limiting
diodes
av
load
regulation.
5-69
ADJUSTMENT
ANI)
CALIBRATION
5-70
Adjustment
·and
calibration
may
be
required.
after
performance
testing,
troubleshooting,
or
re-
pair
and
replacement.
Perform
only
those
adjust-
ments
that
affect
the
operation
of
-fhe
faulty
circuit
and
no
others.
awl) into
the
small
indentation
near
top
of
round
black
plastic
disc
located
directly
below·meter
·face.
c.
Rotate
plastic
disc
clockwise
(cw)
until·
.meter
reads
zero,
then
rotate
ccw
slightly
in
order
to
free
adjustment
screw
from
meter
suspension.
If
pointer
moves,
repeat
Steps
(b)
and
(c).
5-71
METER
ZERO
5-72
Proceed
as
follows
to
zero
meter:
a.
Turn
off
instrument
(after
it
has
reached
normal operating
temperature)
and
allow
ao
seconds
for
all
capacitors
to
discharge.
b.
Insert
sharp
pointed
object
(pen
point
or
5-73
VOLTMETER
TRACKING
5-74
·To
calibrate
voltmeter
tracking,
proceed
as
·follows:
a.
To
electrically
zero
meter,
set
METER
switch
to
highest
CUITent
position
and,
with
supply
on
and no
load
connected,
adjust
R63 until front
5-14
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