HP 8340B Manual page 137

5-4. MIN LOOP, A32, A33, AND A32A1 (Cont'd)
6. Connect DVM to A32TP1 TUNE test point. Refer to Figure 5-8 for location of A32 assembly.
7. Loosen locknut on A32A2C1 FREQ ADJ control and adjust A32A2C1 for a DVM reading of —35.0
Vdc ±0.5 Vdc. Retighten A32A2C1 locknut. Verify that DVM reading is still within tolerance.
8. Press [CW] on the OUT, then enter [2] [3] [0] [0] [MHz].
9. Turn the Spectrum Analyzer's Signal Track off and then set the Spectrum Analyzer for a Center
Frequency of 179.230 MHz. Turn the Signal Track on. The frequency indicated on Spectrum
Analyzer should be 179.230 MHz ±1 count and the OVM should read —2.8 Vdc
10. Set the OUT's LINE switch to STANDBY.
11. Disconnect the DVM from the A32 assembly. Remove the A32/A33 assembly from the instrument
and place it on an extender board.
12. Disconnect the A32 output cable A32A1W1 from A33J3 (Figure 5-8) and connect this cable using
SMB male-to-male adapter to the input of the Spectrum Analyzer. Set the OUT's LINE switch to
ON and press [INSTR PRESET].
13. Turn the Spectrum Analyzer's Signal Track off and then set the Spectrum Analyzer Center Fre-
quencyto 375 MHz, the Frequency Span to 100 MHz, Log Scale 5dB/Division, and the Reference
Level to +5 dBm.
Do not apply a positive voltage to A32TP1 or damage may occur to
the VCO tuning diodes.
14. Connect the low-voltage
this first). Negative lead to A32TP1 TUNE test point. Set the output of the supply for
—35.0
Vdc ±0.5Vdc.
15. Adjust A32A2C5 PWR for a VCO output level of 0 dBm
Analyzer. Refer to Figure 5-8 for location of adjustment.
16. Slowly reduce the voltage output of the external low-voltage power supply connected to
A32TP1 TUNE test point while monitoring the VCO output level on the Spectrum Analyzer
and voltage level on DVM.
17. The VCO output level should be greater than —2 dBm between 395 MHz (—35 Vdc) and
355 MHz (—2.8 Vdc).
18. Repeat Steps 2 through 9 to check frequency accuracy.
19. Set the OUT's LINE switch to STANDBY. Disconnect all the test equipment from the A32/
A33 assembly. Reconnect the cable A32A1W1 to A33J3.
20. Reinstall the A32/A33 M/N Output Assembly and remove the jumper from A59TP4 to
A59TP5 (UNLK indicator disable).
21. Disconnect the cable from the OUT's rear-panel EXT FREQUENCY STANDARD, recon-
nect the BNC cable between the INT and EXT connectors, and set the adjacent switch to
INT.
HP 8340B/41B
power supply to the OUT as follows: Positive lead to ground (do
± 1.0 Vdc.
2 dB as indicated on Spectrum
±
Adjustments 5-25/5-26