13.The voltage at A14U332 pin 2 should be approximately 19% of the voltage at A14523 pin 2.
14.If the 1st LO frequency did not change in step 12, set the HP 8560A’s (LINE) switch OFF and disconnect WlO from A14J3.
15.Place a jumper between A14J3 pins 9 and 10 and set the (LINE) switch ON.
16.On the HP 8560A press (m), STATE, STATE 0.
17.Repeat steps 6 through 13.
18.If the voltage at U332 pin 2 is correct with A14J3 pins 9 and 10 shorted, but was
incorrect with WlO connected, the YTO FM Coil is probably open; replace the All YTO.
19.Replace jumper A14J23.
Roller Oscillator Span Problems (LO Spans 51 MHz)
The following procedure troubleshoots problems with the Roller Oscillator PLL’s Main Oscillator (101 kHz to 1 MHz) and Offset Oscillator (5 100 kHz).
1. Set the HP 8560A to the following settings:
C E N T E R F R E Q . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ...300 MHz SPAN . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ..lMHz RES BW . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10kHz VIDEO BW . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10kHz SWEEPTIME . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50ms
2.Set an oscilloscope to the settings listed below and monitor A14J17 pin 1. The waveform should look similar to Figure
Amplitude Scale . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 250 mV/div Sweep Time . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ..50ms/div
Graph | C | 1 1 | 2 5 0 mV/div | 0 . 0 0 v | 5 0 . 0 0 ms/div | 0 000 s | ||||||
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0 | . 0 0 | s |
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C u r s o r | 0 |
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4 8 4 | mv |
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0 | . 0 0 | s |
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C u r s o r | o - x |
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0 | 00 | v |
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0 | 00 | s |
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S K 1 1 0 6
Figure