Caution: Hands should be clean and
(2) Turn the drum so that the blackest por-
dry. Do not get finger marks on the
tion of the copy is illuminated by the
glazed surface of the paper.
spot of light. Carefully turn the CON-
(2) Warm up the transceiver as outlined
TRAST control to a lower setting until
the meter indicates -6 db. Check the
in paragraph 24a(3).
meter reading. Move the drum back-
Warning: It is possible to overheat or
bum out recorder lamp E2 (fig. 168)
ward and forward slightly while examin-
when setting the GAIN control. Tem-
ing a different black portion of the copy
to be sure the blackest spot is used.
porarily remove it from the circuit by
Caution: Do not turn the CON-
disconnecting the plug at the rear of the
housing in which the recorder lamp is
TRAST control so far that the meter
passes -6 db, and dips to a lower reading
mounted.
before rising again to -6 db.
(3) Operate the dust removal blower switch
to ON in equipment modified by MWO
(3) Move the drum so that the whitest por-
tion of the copy is illuminated by the
11-2258-6 and in Facsimile Transceiver
spot of light. Adjust the GAIN control
TT-1F/TXC-1.
until the meter indicates +2 db. Be
b. Adjustment of GAIN Control.
sure the whitest portion of the copy
( 1 )Turn the selector switch to the RECORD
actually is being used by again rotating
PHOTO position. This makes the fac-
the drum backward and forward slightly
simile transceiver capable of receiving
while checking the meter.
signals without operating the stylus.
(4) Return to the blackest portion of the copy
(2) If the UC coupling coil is being used
and readjust the CONTRAST control
(coupled to a telephone receiver), direct
for a -6 db reading on the meter.
the transmitting operator to send a maxi-
(5) Repeat the procedure in (2), (3), and (4)
mum signal. When the maximum signal
above until- the final adjustment of the
is received, adjust the GAIN control
GAIN and CONTRAST controls give
until the DB METER indicates near
meter readings differing by 8 db between
zero; then rotate the coupling coil on the
the whitest and blackest portions of the
earpiece to the position that gives the
copy. The maximum reading (on white
maximum DB METER reading. Be
copy) must not exceed +2 db. As a
sure the coupling coil is at least 2 feet
final check, slowly cut off the light from
from the transceiver, power supply, and
the exciter lamp; the DB METER indi-
other electrical equipment.
cation should go from +2 db to -6 db
(3) While the transmitting operator is alter-
without going to a value of less than
nately sending maximum and minimum
-6 db.
signals, adjust the GAIN control on the
c. Other Steps. Other steps in the procedure
receiving transceiver so that the DB
for transmitting negative are the same as for
METER indicates from +2 to +4 db on
transmitting positive.
the steady maximum tone. (The test
setting can be learned by experience.)
Note the difference on the receiving
NDA Paper (Direct Process)
transceiver DB METER between maxi-
Direct process recording on Teledeltoe or Time-
mum and minimum signal levels. If the
fax NDA paper does not require reception in a
circuit is functioning properly, this dif-
darkroom and provides a single received copy
ference will be the same as the difference
which can be used immediately without processing.
established at the transmitting transceiver
a. Preparation.
within 2 db.
(1) Wrap the direct process paper around the
Note. The CONTRAST control is not part
drum with the white side of Timefax
of the receiving circuit and does not have to be
adjusted when operating the receiver.
NDA or the metallic side of Teledeltos
toward the drum. The drum loading
c. Phasing Receiver.
operation is essentially the same as for
(1) Be sure the STANDBY-MON-TALK
transmitting (par. 24).
switch is at MON. Operate the START
