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44.)
15
1
000 cycles
. 48
1
FM Noise:
- 68
DB
AM Noise:
Better Than - 70 DB
MAINTENANCE
Since moving parts are at a minimum in the exciter unit routine
maintenance is a simple procedure.
The few moving parts that
are used,
such as,
variable capacitors,
potentiometers and var-
iable inductors will perhaps stay set in one position for the
life of the exciter unit.
The one exception to this would be
C103 the frequency adjust control.
Because routine maintenance is used to prevent trouble and not
start it,
it is not deemed advisable to poke and pull at every
component part at a pre- arranged time.
Tubes are the most like-
ly components to go bad.
A routine testing of all of the tubes
at least once every six months is recommended.
One of the best ways to foretell trouble is by test point
voltages.
These are recorded on the factory test data sheet.
When the exciter is first received and placed into operation,
it is advisable to go over these test point voltages and re-
cord the reading obtained.
The test point voltages should
then be checked weekly or monthly.
A substantial variation
from the original recorded value would indicate a failing
tube or other component in that circuit.
These voltage
measurements should always be made with the same meter
since a normal 10% variation from one meter to the next
may be expected.
An occasional check on the noise,
distàrtion and response
with a test set up such as shown in drawing A-4165 will
probably reveal an eminent failure of one of the audio
stages or one of the pulse stages
V101 thru V106.
When tubes are checked and replaced, it is wise to replace
them in their original sockets.
If V113, V114 or V115 is
changed,
it may be necessary to retune associated circuitry
for best performance.
TROUBLE SHOOTING
It would be impossible to list every failure and possible
-19-
M6095 Exciter
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