TSP #47 - Teardown, Repair and Analysis of an HP 8562B 22GHz Spectrum Analyzer

In this episode Shahriar repairs an HP 8562B 22GHz spectrum analyzer. This spectrum analyzer has two input bands. The lower band which operates from 1kHz – 2.9GHz shows does not operate correctly and does not display any signal. The internal construction as well as the operation of the unit is explained along with a close look at LO distribution, input attenuator, dual-mixer and various filters.
During the debugging procedure it is also discovered that the Second Mixer is also damaged in this unit. A replacement unit was purchased however a replacement unit for the main first converter is too expensive to replace. As an alternative, a Mini-Circuit mixer is used as a replacement. The LO signal is routed to the external mixer via a microwave switch. In this configuration the LO is automatically switched to the correct mixer for each frequency band of operation. The unit is then verified for correct operation.

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