Advertisement
THEORY OF OPERATION
When the low voltage " On" button,
S502,
is pressed on the 1 KW
control panul,
contactor, K501
1
is energized.
When K501 is
energized,
line voltage is applied to the cabinet fan, blower,
primary to all filament transformers,
the low voltage power
supplies and the exciter power supply in the left cabinet.
With the energizing of K501,
K804 in the amplifier control cab-
inet is also energized.
With the energizing of K804,
the pri-
mary circuit is complete to K602
1
which is the blower off de-
lay relay.
Also,
when K 602 energizes, K601,
which is the
blower starting relay,
will also energize.
With the energi
z
ing
of K601 the blower will start.
As the blower comes up to
speed,
S 605,
which is the air switch,
will close.
With the
closing of the air switch,
the auxiliary filament contactor
K806 will thon close and complete the primary circuit to the
P.À..
filament transformer.
2-Lt this time all low voltage supplies,
fan,
blowers and tube
filnments should be operating.
This will be indicated by the
lights on the control panels of the driver and the power amp-
lifier.
all of these lights are not on,
high voltage to the driver
or the amplifier can not be
applied.
This condition will occur if these conditions are satisfied:
1.
All door interlocks closed.
2.
Grounding hooks in place.
3.
Both air switches closed.
4.
Voltage applied to tie filament transformers.
5,
Grid bias developed in the driver.
6.
Sufficient fixed bias developed by the P.L.
supply.
Because of the nature of this control circuitry,
all functions
in the driver :lust be complete before
7
ny indications occur on
the P.A.
control panel.
With the closing of S506 the high voltage " on" button on the 1KW
control panel,
K503 is energized and both plate and screen vol-
tages are applied to the driver.
With the pressing of S704,
the high voltage " on" button on the power amplifier control
panal,
K805 is energized and plate voltage is applied to the
power .amplifier.
6/22/61
-7-
FM -20 D
Advertisement
