Western Electric 6-B, Инструкция по эксплуатации

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lead or ground have corroded, introd ucing a high resistance in the antenna­
ground system. Inspection of all contacts in this system should be made, and
imperfect contacts eliminated. Rectuced radiation may al so be caused by dirty
insulators wh ich provide a h igh resistance leak to ground. The antenna should
be lowered and the insulators cleaned or replaced. If reduced rad iation is unac­
compan ied by a change in antenna current it is probably due to a seasonal or
atmospheric condition whi ch ·will eventually right itself.
Devia tio n Fro m A ssigned Frequ e n cy
The deviation of the carrier freqllency from its assigned frequent.\' i s
u sually due to the fai l u re of the temperature control equ i pment. T h e tem pera­
ture should be observed to see that it is at the operating: value spec i fied for the
particular crystal. A log of the temperature of the crystal during operation
should be carefully maintained and any deviation in temperatu re promptly
corrected.
Frequency deviation m ay also be caused by poor contact of the l ower elec­
trode of the No. D-87781 Q uartz Oscillator with the metal mounting block of
the thermal element, thus effectively lowering the temperature of the crystal .
Care should b e taken that the lower electrode i s clamped t ightly t o the metal
mounting block. If the retaining clips on the metal mounting block lose their
tension, squeeze them towards th e center of the block.
Do n o t l> e 1 1 d the cli1>s .
Failure o f t h e N o .
D-87781 Qua rtz
Oscilla tor
Should either q uartz oscillator cease to operate as indicated by zero oscilla­
tor grid c urrent, it should be inspected for a defective crystal or for dirt between
the crystal and electrodes. The procedure for inspecting, cleaning and replacing
crystal is outlined on page 55. If the crystal is defective, it should be replaced.
If dirt is present, the crystal, housing and electrodes should be cleaned as
described on page 55.
Intermittent operation of the q uartz oscillator is usually due to a bad con­
nection. All connections between the quartz oscillator terminal and the grid
terminal of the oscillator tube should be carefully inspected, and loose connec­
tions should be corrected.
NOTE :
T o assure that both quartz osc i ll·ators are i n operati ng con d i tion the position o f
t h e " C RYSTAL S E L E CTOR" sv.itch should be changed periodical ly.
Temperature Con trol Equipmen t
Should the temperature rise to an abnormal value, the operator should
check the operation of the relay in accordance with the simple test that is out­
lined on page 37. If the relay is functioning properly, the trouble is probably
due to dirty thermostat contacts. Turn "HEATER SUPPLY SWITCH OFF."
First remove the thermom ete1', then remove the thermal element with the
attached No. D-87781 Quartz Oscillator from the heat insulated chamber. Clean
the contacts of the thermostat in accordance with the procedure outlined for
the cleani ng of relay contacts on page 57.
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