5-6
5.5 QSK BOARD A11 (81949) This board contains the low voltage supply, turn-on relay
sequencing circuits, and T/R relay control.
The low voltage is rectified by D1 – D4 and filtered by C6. U1 and Q2 provide regulation
for all low voltage circuits except the negative 16 VDC supply.
After a 3 minute warm-up period determined by RC time constant of R4 and C5,Q19 and
Q11 will conduct, turning on the pass element Q7. This initiates amplifier power up.
When the STANDBY/ OPERATE switch is put in the OPERATE position, this voltage is
applied to relay sequencing circuits Q3, Q6, Q4 and Q10. These circuits insure plate and
screen voltages arrive at and leave the tube in the proper order.
Q20 senses plate current and disables the amplifier when plate current parameters are
exceeded (such as excessive plate current during a tube arc). Both plate voltage and screen
voltage are removed when plate current of 1.5A is reached.
The QSK CONTROL CIRCUIT consists of Q12-Q18 and Q21-Q23. This circuit samples
input key requests, standby/operate modes, power on/off state, state of output relay, and RF
presence at the antenna connection and input of the amp. Hot switch protection is provided
regardless of mode. In the QSK mode, using the key in / key out loop, the key in request
from the transceiver is tailored by the QSK CONTROL circuit to insure smooth QSK action
of the input and output relays.
K2 senses power OFF or STANDBY and places the key circuit in bypass for operation in
barefoot mode.
K3 senses OPERATE mode and routes the key request to the amplifier control circuits.
K4 passes the “key in” to the KEY OUT jack when all relays are closed and ready for RF.
FIGURE 5-7 QSK BOARD (ASSEMBLY A11) COMPONENT
LAYOUT TOP VIEW
Содержание TITAN III 417
Страница 19: ...2 6 BAND FREQUENCY LOAD TUNE ANTENNA NOTES FIGURE 2 2 MODEL 417 TUNING LOG ...
Страница 20: ...2 7 FIGURE 2 3 TITAN III FRONT VIEW FIGURE 2 4 TITAN III REAR VIEW ...
Страница 21: ...2 8 FIGURE 2 5 TITAN III TOP VIEW ...
Страница 22: ...2 9 FIGURE 2 6 TITAN III BOTTOM VIEW ...
Страница 32: ...5 7 FIGURE 5 8 QSK BOARD ASSEMBLY A11 TOP AND BOTTOM CIRCUIT TRACES VIEWED THROUGH BOARD FROM TOP ...
Страница 38: ...5 13 TOP COPPER BOTTOM COPPER FIGURE 5 18 AC LINE DELAY BOARD ASSEMBLY A9 CIRCUIT TRACE TOP VIEW THROUGH BOARD ...
Страница 40: ...5 15 FIGURE 5 21 SCHEMATIC DIAGRAM MODEL 417 ...
