HP 8562E Service Manual page 299

Refer to function block B of A3 Interface Assembly Schematic Diagram in the
HP 8560 E-Series Spectrum Analyzer Component Level Information.
The ADC Start/Stop Control determines the start time of all ADC conversions. Multiplexer
ASM to start a conversion.
1. Press (PRESET) on the spectrum analyzer and set the following controls:
Span . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . OHz
Sweep time . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60 s
Detector mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . SAMPLE
2. Check for a TTL high at A3U509 pin 2 and a TTL low at A3U509 pin 14.
3. Set the detector mode to NORMAL.
4. Check that A3U509 pins 2 and 14 are both TTL low.
5. Set the spectrum analyzer to the following settings:
Span . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ..lMHz
Detector mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . SAMPLE
6. Check for a TTL high at A3U509 pin 2 and a TTL low at A3U509 pin 14.
7. Press (CAL) and RF&J&N LO & IF. During the realignment, A3U509 pin 2 should be
TTL low and pin 14 should be TTL high until the 10 kHz and narrower resolution
bandwidths are adjusted. If correct, the Start/Stop Control circuitry is being selected
properly by the processor and U508 in the ADC Register block is working properly.
8. Press (PRESET) on the spectrum analyzer and set the controls as follows:
Span . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . OHz
Detector mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . SAMPLE
Sweep time . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 400ms
9. Check that A3U509 pin 7 has positive 15 ps pulses with a 667 ps period (sweep
(sweep time/600). The p 1 u ses should be present during the sweep but absent during
retrace.
10. Set the detector mode to NORMAL.
11. Check that A3U509 pin 9 has pulses every 130 ps and U509 pin 7 has pulses every 667 ps
(although pulse widths may be changing).