7.If a correct signal is seen at A15TP201 but the signal at A15TPlOl is wrong, proceed as follows:
. Use an oscilloscope to measure the signals at the following test points:
A15J400 pin 1t1.8 Vdc to t2.4 Vdc (LO.5
A15J400 pin 3-1.8 Vdc to
If these levels are wrong, perform the “Power and Sampler Match Adjustments” in the Sampler Oscillator Adjustment procedure. Refer to Chapter 2.
If adjusting the Sampler Match does not bring the signal at Al5TPlOl within specification when the signal at A15TP201 is correct, the A15A2 Sampler is defective.
8.If the signal at A15TPlOl is correct, but the signal at A15JlOl is wrong, the fault lies in the Sampler IF circuitry. Continue with the following steps.
9.Set the HP 8560A to the following settings:
C E N T E R F R E Q . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ...300MHz SPAN . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . OHz
10. Set a microwave source to the following settings:
Frequency . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.2107GHz Amplitude . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
11.Connect the microwave source to A15A2Jl.
12.Measure the signal at U103 pin 1 using an active probe/spectrum analyzer combination.
13.If a 94.7 MHz signal, approximately
14.When U104 pin 3 is at TTL low, U104 pin 6 should near
15.Set HP 8560A to the following settings:
C E N T E R F R E Q . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .89.3MHz SPAN . . . . . . . . . . . . . . . . . . . . . . . . . . , . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0 Hz
16.Check that U104 pin 3 is at a TTL high and U104 pin 6 is greater than +7 V. PIN diodes CRlOl, CR102, and CR103 should all be turned on with about 7 mA of forward current.
17.Disconnect the power splitter and reconnect W32 to A15JlOl.