RECORD DIRECT settings of the se-
V11 through coupling capacitor C38 and
lector switch. This meter is disconnected
limiting resistor R65. Resistor R65 is
in the STANDBY position of the selector
in the circuit to prevent the grid from
switch.
drawing current when the plate circuit is
not energized; that is, when the selector
The record output amplifier, V14 (type 1635), a
switch is in some position other than in
Class B power stage, drives the recorder lamp on
the RECORD DIRECT position. Dur-
the RECORD PHOTO setting of the selector
ing operation of the stage, the grid is not
switch, and drives the stylus on the RECORD
fed sufficient signal to drive it positive
DIRECT setting of the selector switch. These
and cause grid current to flow through
grid resistor R64. Bias for the stage
two outputs are plate circuit outputs A separate,
cathode circuit output is taken during the phasing
(approx. 18 volts) is developed by the
operation (when the PHASE switch is operated)
flow of cathode current in stage V13 and
and is applied to cathode-driven pulse amplifier
motor amplifier stage V4. In Facsimile
Transceivers TT-1/TXC-1 and TT-1A/
driven through secondary No. 1 of transformer
T X C - 1 , V4 cathode current flows
T2 by stage V12 when the selector switch is in the
through resistors R66 and R67. The
RECORD PHOTO position and by stage V13 in
bias on V13 is the voltage developed
t h e RECORD DIRECT position. A type
across R67. In Facsimile Transceivers
TT-1B/TXC-1 through TT-1F/TXC-1,
6AC5GT/G tube was originally used in Facsimile
Transceivers TT-1/TXC-1 and TT-1A/TXC-1,
V4 cathode current flows through resis-
but was replaced in these equipments with a type
tors R66, R67, and R97 (fig. 56). The
1635 tube (MWO SIG 11-2258-2) because of fre-
bias on V13 is the voltage developed
across R67 and that portion of poten-
quent failure.
tiometer R97 which is in the V13 cathode
secondary No. 1 of T2 is applied to grids
circuit. Control R97 can be adjusted
for best operation of the stage. The
No. 4 and 5 in parallel. Plate voltage
cathode resistor is bypassed by capacitor
is applied from the regulated +250-volt
C42. Only when the selector switch is
supply through the recorder lamp (E2)
in the RECORD DIRECT position is
and resistor R94 in parallel (modified
plate current supplied to this section of
Facsimile Transceivers TT-1/TXC-1 and
V13 through section S1D of the selector
TT-1A/TXC-1 have resistor R94). The
switch and the primary of transformer
stage is biased Class B, so that with no
T2, which now becomes the Class B
signal input, the recorder lamp produces
driver transformer for stage V14.
only a slight glow. The recorder optical
(2) Meter amplifier. The grid (pin 4) of the
system uses recorder lamp E2, tube
meter amplifier tube, triode section 2, 3,
R1130B, which is a neon-filled lamp,
and 4 of V13, is fed at all times by the
capable of converting varying signal in-
voltage across R62 in the grid circuit of
tensities into varying amounts of light.
stage V12. Capacitor C41 is the input
The lamp is mounted in a housing (A,
coupling capacitor and R68 is the grid
resistor for this section of V13. The
plate and field lens at one end of a lens
DB METER, an ac meter with a self-
barrel. On the other end of the barrel
contained copper-oxide rectifier, receives
is an objective lens which focuses the
its signal from the shunt-fed plate circuit
light passing through the aperture to a
of the stage. The plate is supplied from
small spot on the film or photographic
the regulated +250-volt supply through
paper. The recording beam produces ex-
plate load resistor R69. Capacitor C43
posures in accordance with its intensity.
couples the modulated 1,800-cycle signal
from the plate to the meter through R70
this position is applied from record direct
for the TRANSMIT and SET RANGE
amplifier driver V13 through the selector
positions of the selector switch and through
switch. Plate voltage is supplied from
R71 for the RECORD PHOTO and
the unregulated +450-volt supply
