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Sect.IV
Page 12
4-9
METER
ZERO
ADJUSTMENT
Both meters
should read zero when the instrument
is turned
off.
If both of the meters do not read
zero proceed as follows:
Preheat instrument and turn off -
A mechanically stable adjustment can only be made
when
the direction
of pointer travel is opposite to
the direction of rotation of the adjust screw.
The
adjusting screw may be turned in either direction,
but a good way is to turn the screw clockwise until
the pointer swings up scale and then starts to swing
down scale toward zero (i.e.:
counterclockwise).
Continue
turning
the
screw
clockwise
until
the
pointer (now moving to the left) is directly over the
zero mark.
If you go too far, continue turning the
screw Clockwise until the pointer is again traveling
down scale towards zero.
4-10
GENERAL
TEST
AND
ALIGNMENT
INSTRUCTIONS
Usually
a
particular
instrument
will
not
need
complete test and adjustment, Thisis particularly
true
when repair has been accomplished
without
changing any internal adjustments. BEFORE MAK-
ING ANY
INTERNAL ADJUSTMENTS, READ ALL
OF
PARAGRAPHS
4-1 and 4-4.
If unnecessary
adjustments are eliminated
you will often save
time by being able to finish a repair without com-
pleting the entire test and adjustment procedure,
The
procedures
are
listed
in a recommended
sequence for a complete test and adjustment oper-
ation,
Test instrument recommendations are given
in paragraph 4-8, Test Equipment Required.
The
test frequencies
and voltages are based upon the
use of these recommended
instruments.
If other
equipment
is substituted,
you may have to alter
the procedures
accordingly.
When other equip-
ment
or
methods
are
used,
it is important
to
select components and techniques which have equal
or greater accuracy.
Any instrument can be ad-
justed
for optimum
performance at a particular
frequency or voltage, or the most commonly used
range.
The specifications for your instrument are given
in the front of this manual.
The test procedures
contain
extra checks to help you analyze a par-
'ticular
instrument,
These extra checks
and the
data they include
are
not
to be considered
as
specifications,
Model 606A
A ten to fifteen minute warmup at normal line volt-
age
(nominally
115/230
volts) and power supply
output voltage measurements
are always
recom-
mended
before making any other tests or adjust-
ments.
Refer to paragraph 4-11] before making any
power supply adjustments.
4-11
POWER
SUPPLIES
The power supplies in this instrument are extremely
stable and will require infrequent adjustment,
The
output voltages may be measured at regular inter-
vals
or
as a first trouble-shooting step but un-
necessary adjustment should be avoided. A defective
tube or component may overload the power supply
and lead you to believe that the power supply is not
functioning properly.
As long as the power supply regulator is function-
ing properly, you need not know the absolute values
of the power supply output voltages. However, when
power supply adjustment is necessary, you should
use a voltmeter with a known calibration accuracy.
Regulation of the power supply can be checked by
varying
the power
line voltage between
103 and
127 volts. The output voltage will vary only slightly,
if at all, from the value measured with a 115 volt
line.
Loss
of power
supply
regulation
is most
easily detected,
as
a sudden
large
increase
in
power supply ripple as the line voltage is raised
and lowered +10% from 115 volte
When the power supply output voltages are within
limits with the line voltage at 115 volts, adjustment
is not necessary.
Do NOT adjust in an attempt to
refine the existing control settings.
To
test
the power
supplies proceed as follows:
1) Measure
power
supply outputs,
They should
be within the limits shown in Table 4-5,
2) If the voltage is outside the limits in the table
adjust
R126
(-200 V Set) for -200 volts.
This
control is in the center of the power supply deck
with access only from the front side of the chassis.
3) You may wish to check the regulation of each
power supply as the line voltage is varied between
103 and 127 volts.
All regulated voltages should
remain within +1% over this range of line voluge.
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