HP 8753E Service Manual

Check 1st LO Signal at Sampler/Mixer
If the 4 kHz signal is bad at the sampler/mixer assembly, check the 1st LO signal
where it enters the sampler/mixer assembly in question.
q If the 1st LO is faulty, check the 1st LO signal at its output connector on the
A7 assembly to determine if the failure is in the cable or the assembly.
q If the 1st LO is good, continue with “Check 2nd LO SiiaI at Sampler/Mixer”.
Check 2nd LO Signal at Sampler/Mixer
Check the 2nd LO signal at the pins identified in ‘0ble 8-3. Refer to the “Al2
Reference Check” in Chapter 7, “Source Troubleshooting”, for analog bus
and oscilloscope checks of the
2nd LO and waveform illustrations ‘Ihble 8-3
identifies the signal location at the samplers and the Al2 assembly.
‘Ihble 8-3. 2nd LO Locations
Mnemonic
Description
ZndL01
2nd Lo (0 degrees)
2nd Lo 2
2nd Lo ( - 9O degrees)
Sampler
LOCdl0n
A4/6/6 Pl-11
A4lbl6 Pl-4
SW
soluce
Al2Pl-2, 32
Al2Pl-4, 34
If the 2nd LO is good at the sampler/mixer, the sampler/mixer assembly is faulty.
Otherwise, troubleshoot the Al2 assembly and associated signal path.
8-14 Receiver Troubleshooting

HP 8753E Specifications

General

Brand	HP
Model	8753E
Category	Measuring Instruments
Language	English