
SG-2000 MANUAL
176
The SGC Building, 13737 S.E. 26th St. Bellevue, WA. 98005 USA
©1995, SGC, Inc.
TEL: (206) 746-6310 FAX: (206) 746-6384
Note on using HP8443A Tracking Generator as an RF generator
The HP8443A Tracking Generator can substitute for an RF Generator with changes to
the following settings:
•
If connected to the Spectrum Analyzer, turn CRT intensity on Analyzer to
minimum.
•
(Scanning) Mode = scan hold.
• Set RF Out to -3 dB before transmitting. Adjust the RF out only when not in
transmit.
Open the windings on inductors L1 through L15 to their maximum.
Use the multimeter in the Ohms position. Make the following readings with
reference to ground.
Check that all pins on J15 except 5 and 6 are connected to GND and have a
resistance = 1 K
Check for the following values:
IC5 pin 1 approximately 10 K
IC5 pin 5 approximately 2.0 M
IC5 pin 7 approximately 2.0 M
Fuse F3 output
> 1.0 M
Collector Q6, Q7, Q10, Q11 > 500 K
Base Q6, Q7, Q10, Q11 ˜ 11.2 ?
Pin 4 of IC2
> 400 ?
Base Q2 and Q3
˜ 23 ?
23.2.4
Voltage Protection (Rev E Boards ONLY)
Note: Safety glasses should be worn while testing the voltage protection circuit.
•
Out of Range Voltage Supply
(Rev E and Later Boards ONLY)
Use the variable power supply set on the lowest voltage setting. Connect the
positive power lead to J12. Connect the negative power lead to J14.
Watch the current meter on the power supply as you turn on the power supply.
Turn off the power supply if I = 1A and troubleshoot the problem. Increase the
supply voltage until relay K14 closes. Record the supply voltage. Continue to
increase the voltage until relay K14 opens again. Record the supply voltage.
Relay Closes
between
9 and 10.5 Volts
Relay Opens
between
19 and 20 Volts
Increase the voltage to 40 V, keep it there for 3-5 seconds and decrease to 0.
Observe K14 turning on and off when it reaches the above voltages.