Harris Gates Five 994 9204 002, Техническое руководство

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assembly, examine resistors for dirt
or signs of overheating. Discolored,
cracked, or chipped components indi-
cate a possible overload.
When replacing a resistor, ensure that
the replacement value corresponds to
the component designated by the
schematic diagram and parts list.
Clean dirty resistors with a small
brush.
VARIABLE TUNING AND LOADING
COILS. Lubricate at six month intervals, or
as required if binding is evident, the mating
surfaces of the ribbon and wiper with HAR-
RIS lubricant (part number 055 0115 007)
using a cotton swab to apply the liquid.
Follow directions provided with lubricant
for proper application techniques. Use spar-
ingly as too much may prove ineffective.
This lubricant can also be obtained locally
or from CAIG LABORATORIES, INC.,
Escondido, CA., 92025-0051 under the
name of CRAMOLIN R.
FUSES. Preventive maintenance is ac-
complished by performing the following
steps:
When a fuse blows, determine the cause
before installing a replacement.
CAUTION
IF ANY OF THE FUSES IN THE GATES SE-
RIES™ TRANSMITTER REQUIRE REPLAC-
ING, ENSURE THAT ONLY AN EXACT RE-
PLACEMENT FUSE IS USED. A DIFFERENT
MANUFACTURER’S FUSE OF THE SAME
SIZE AND/OR RATING DOES NOT FULFILL
THE REQUIREMENT FOR EXACT REPLACE-
MENT.
Inspect fuse caps and mounts for charring
and corrosion.
Examine clips for dirt, and, if necessary,
clean with a small brush.
If necessary, tighten fuse clips and con-
nections to the clips. The tension of the fuse
clips may be increased by pressing the clip
sides closer together.
SWITCHES. Preventive maintenance of
switches is accomplished by performing the
following steps:
Inspect switch for defective mechanical
action or looseness of mounting and con-
nections.
Examine cases for chips or cracks. Do not
disassemble switches.
Inspect accessible contact switches
for dirt, corrosion, or looseness of
mountings or connections.
Check contacts for pitting, corrosion,
or wear.
Operate the switches to determine if
they move freely and are positive in
action.
Tighten all loose connections and
mountings.
Be sure to include an inspection of
the power supply discharge switches
located at the bottom of the rear
panel opening.
TOROIDS. Inspect the drive transformer
assemblies periodically for any signs of
stress. These would be T11 and T12 on the
IPA and T11, T12, T21, T22, T31, T32, T41,
and T42 on the Power Amplifier boards A1
through A4. In particular, check the zener
diodes on these transformer assemblies for
signs of over dissipation. When over dissi-
pated, these zeners will lose their normal
glossy finish. If any of these zeners are
found in this condition, check the RF drive
system.
The toroids on the backside of the IPA and
PA should be inspected when the modules
are removed for replacing transistors. A
crack or break in any core may cause dam-
age to the transistors of the same quad. The
best way of inspecting the toroidal cores is
by rotating the core. This will allow a com-
plete visual inspection.
PRINTED-CIRCUIT BOARDS. Pre-
ventive maintenance of printed circuit
boards is accomplished by performing the
following steps:
Inspect the printed circuit boards for
cracks or breaks.
Inspect the wiring for open circuits
or raised foil.
Check components for breakage or
discoloration due to overheating.
Clean off dust and dirt with a clean,
dry lint-free cloth.
Use standard practices to repair poor
solder connections with a 40 watt
soldering iron.
CAUTION
ENSURE THAT THERMAL COMPOUND IS
APPLIED TO PLATES OF PA, IPA, AND PDM
AMPLIFIER BOARDS BEFORE THEY ARE IN-
STALLED ON HEAT SINKS AND THAT HARD-
WARE SECURING BOARD TO HEAT SINK IS
PROPERLY TORQUED TO 6-INCH POUNDS.
ALSO INSURE NO BURRS OR DIRT PARTI-
CLES ARE ON THE MATING SURFACES.
3.3.2.
Air System
The air filter should be cleaned routinely.
The intervals between cleaning will depend
on the environment.
Replace filter if it is worn out.
3.3.3.
GATES Series™ Top Removal
Procedure
The GATES Series™ top may have to be
removed to change frequency determinant
components if a frequency change is re-
quired, or any capacitors need replacing.
WARNING
ENSURE ALL POWER IS REMOVED AND
N E T WO R K
C O M P O N E N T S A R E
SHORTED WITH SHORTING STICK BE-
FORE PERFORMING THE FOLLOWING
PROCEDURE.
a. Make sure all power is turned off and
Output Ne twork com ponents are
shorted to ground with shorting stick.
b. Disconnect A21L1 in the Output Net-
work from PA module A1 (see Figure
3-2).
c. Remove the eight screws holding RF
shield below L2 and remove RF shield
from transmitter.
d. Disconnect the tubing which connects
A21L7 to the TUNING control, L4 as
shown in Figure 3-3.
e. Remove 10-32 Phillips head screw from
C3 connector strap that goes to L4 (see
Figure 3-3).
f. Separate the two halves of A18P4. This
connector is in line with three coaxes
which go from the bracket end of A21
L2 to the Output Monitor board (see
Figure 3-2).
g. Disconnect gray wire #112 from the HV
shorting switch at the upper left of the
rear opening.
h. Remove all of the 8-32 screws around
the perimeter of top access panel and the
eightr screws on the top rear (see Figure
3-1).
CAUTION
THE REMOVABLE TOP ASSEMBLY WEIGHS
APPROXIMATELY 46 POUNDS.
i. From the rear of transmitter, pick up on
the top and pull complete assembly back
about one inch. It may be necessary to
pull slightly on top back section to dis-
engage edges from guide slots in corner
posts.
j. At this point it may be more desirable to
grasp bottom of L2 with one hand and
top back section with the other hand. Lift
top rear about one inch and pull com-
plete assembly straight back and then
down to desired work area.
k. Reinstall the GATES Series™ top by
reversing the above procedure.
3.3.4.
Low Voltage Supply Adjustment
The Low Voltage power supply outputs
need to be in the desired voltage range in
order for the transmitter to work properly.
One Low Voltage Supply output is +/-20
volts for use by the Controller, PDM Gen-
erator, RF Oscillator, PDM Amplifiers,
Output Monitor, and Interface board.
The other output from the Low Voltage
Supply is for use by the IPA and is 60 to 120
3-2 888-2314-001 Rev. AD
WARNING: Disconnect primary power prior to servicing.