HP 8753E - Troubleshooting When au Inputs Look Bad

Troubleshooting When All Inputs Look Bad
Run Internal Tests 18 and 17
1. Press (Preset) ~ ~~~I~~~~.~~ ~~~~ Llsl Lxl) ~~~~~~ to I-un
- . ..-.................-... .._...._... - .._. -...
;:... .._........
the ADC offset.
__ _ _ ~~.
2. Then, when the analyzer finishes test 18, press L17) Lxl) .~~~~~~~~ to
run the ADC linearity test.
If either of these tests FAIL, the A10 assembly is probably faulty. This can be
conflrmed by checking the 4 MHz signal and substituting the A10 assembly or
checking the signals listed in Table 8-l.
Check 2nd LO
Check the 2nd Lo signal. Refer to the “Al2 Reference Check” section of
Chapter 7, “Source Troubleshooting” for analog bus and oscilloscope checks of
the 2nd Lo and waveform illustrations.
q If the analyzer passes the checks, continue to “Check the 4 MHz REF Signal”.
q If the analyzer fails the checks, perform the high/Iow band transition
adjustment. If the adjustment fails, or brings no improvement, replace A12.
8-6 Receiver Troubleshooting