HP 8560A, Руководство по обслуживанию

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A7 LODA (LO Distribution Amplifier)
Note
YTO unlock errors may occur if the power delivered to the Sampler is
less than -9.5 Frequency response will be degraded in both internal and
external mixing modes if the output power is low or unlevelled.
Caution Connecting or disconnecting the A7 LODA’s bias with the HP 8560A
switch on will destroy the A7 LODA. Always set the HP 8560A (LINE switch
off before removing or reinstalling W12 to either the A7 LODA or
Note Error 334 may be displayed if the LO OUTPUT connector on the front panel
is not properly terminated into a termination.
1. Set the HP (LINE) switch to off. Disconnect W12 from
2. Connect a jumper between pin 5 and pin 6. Connect a jumper between
pin 13 and pin 1.
3. Connect a positive lead to pin 14 and the negative lead to pin 6.
4. Set the HP HP 8560A’s switch to on.
5. The voltage measured on the DVM should be more negative than -9.4 Vdc.
6. Move the jumper from pin 1 to pin 2. The voltage measured on the DVM
should be more positive than Vdc.
7. If the voltages do not meet the limits listed in steps 4 and 5, troubleshoot the Al4
Frequency Control assembly.
8. Connect the positive DVM lead to pin 1.
9. The measured voltage should be approximately Vdc. If the voltage is not Vdc,
troubleshoot the Al4 Frequency Control Assembly.
10. Connect the positive lead to pin 1. The voltage should measure within 5%
of the GATE BIAS voltage listed on A7 LODA’s label.
11. If this voltage is not within this range, rotate GATE BIAS through its range
while monitoring the DVM.
12. If the voltage varies between 0 Vdc and -2 Vdc, adjust GATE BIAS for a DVM
reading within 5% of the GATE BIAS voltage listed on A7 LODA’s label. If the voltage
does not vary between 0 Vdc and -2 Vdc, troubleshoot the Al4 Frequency Control
assembly.
13. Disconnect the jumper from to Set the switch off. Reconnect W12
to Set the (LINE) switch on.
14. If the DVM reading changes significantly, the A7 LODA is probably defective.
11-6 RF Section