Symptom
Probable trouble
Correction
18. Frequency deviationn output is
i
DEV CAL potentiometer R6
Adjust R6 and check adjustment of
correct but does not coincide with
misadjusted.
R8 and R13.
indication on KILOCYCLES -
Defective V1 or V2
Check and, if necessary, replace V1 or
DEVIATION meter in all positions of
V2.
the DEV MULT switch.
A defective part in the circuitry of
Make a voltage and resistance mea-
V1 or V2.
surement at the tube sockets of V1
and V2.
19. Frequency deviation in output is
X1 ADJ potentiometer R13
Readjust R13.
correct and coincides with indication
misadjusted.
on KILOCYCLES DEVIATION
X5 ADJ potentiometer R8 -
Readjust R68
meter in X10 position of DEV
misadjusted.
MULT switch, but does not coincide
X1 position, defective R11, R13, or
Replace defective part.
with meter reading in X1 or
R14.
X5 position.
In X5 position. defective RS, R9,
Replace defective part.
R10, or R12.
20. For a given setting of the DEVIATION
DEV COMP potentiometer R65 is
Adjust R65.
control, the output fre-
misadjusted.
quency deviation varies as the out-
A defective part ill the circuitry of
Make a voltage and resistance mea-
put carrier frequency is varied
V10 or V11.
surement at the tube sockets of V10
through the tuning range.
and V11.
R66 defective .
Replace R66.
21. Modulated rf output is distorted
Defective tubes V3, V4, V10, and V11
Substitute tubes known to be good.
A defect in the circuitry of the above
Make voltage and resistance measurements
mentioned tubes.
at the tube sockets of the above
tubes.
BIAS ADJ potentiometer R100
Adjust R100.
misadjusted.
R27 misadjusted
Adjust R27.
E1 defective
Replace E1.
Section II. REPAIRS
screws (fig. 21) which secure the cover plate to the rf
60. Replacement of Parts
assembly.
readily accessible and can be replaced easily. Tag wires 61. Disassembly and Assembly of Rf Assembly
a. To remove the rf assembly, proceed as follows:
to prevent wrong connections whenever replacement
(1) On the dial cover, remove the dial lock,
requires the temporary removal of wiring.
TUNING dial and knob, and 200-400MC
b. To gain access to the interior of the signal
TRIMMER knob (fig. 5).
generator, the left side, top, and bottom covers must be
(2) Remove the dial cover by removing the four
removed. Remove the left side cover by loosening the
screws which secure it to the front panel.
six captive screws which secure it to the frame. After
(3) Remove the hairline window which is held in
removing the left side cover, the top and bottom covers
place over the FREQ. IN MEGACYCLES
may be removed by sliding them out of position.
dial by two screws.
c. To gain access to the rf assembly, pull off the
(4) Remove the FREQ. IN MEGACYCLES dial
outer and inner rf shields. This permits access to all tube-
by removing the three screws which secure it
socket pins. To gain access to the components in the
to the hub.
oscillator and first doubler, remove the cover plate from
41
