HP 8560A, Service Manual

Page: 362 / 450

13. The voltage at 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 from
15. Place a jumper between pins 9 and 10 and set the (LINE) switch ON.
On the HP 8560A press
STATE, STATE 0.
17. Repeat steps 6 through 13.
18. If the voltage at U332 pin 2 is correct with pins 9 and 10 shorted, but was
incorrect with connected, the YTO FM Coil is probably open; replace the All YTO.
19. Replace jumper
Roller Oscillator Span Problems (LO Spans MHz)
The following procedure troubleshoots problems with the Roller Oscillator Main
Oscillator (101 to 1 MHz) and Offset Oscillator
100
1. Set the HP 8560A to the following settings:
C E N T E R F R E Q . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ...300 MHz
SPAN . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
RES BW
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
VIDEO BW . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
SWEEPTIME . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50ms
2. Set an oscilloscope to the settings listed below and monitor pin 1. The waveform
should look similar to Figure 10-6.
Amplitude Scale . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 250 mV/div
Sweep Time . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Graph 1 1 2 5 0 0 . 0 0 v 5 0 . 0 0 0 000
1 :
X S e l e c t e d
4 8 4
0 . 0 0
C u r s o r 0
4 8 4
0 . 0 0
C u r s o r o - x
0 00 v
0 00
S K 1 1 0 6
Figure Input to YTO FM Coil Driver
Synthesizer Section