In this episode Shahriar repairs an Agilent N9020A MAX Spectrum Analyzer. The instrument is well equipped with real-time capability and direct I/Q input ports on the front panel. The instrument does not show the correct signal levels and fails internal calibration.
After a brief teardown, the block diagram of the instrument is carefully examined for potential failure points. It is determined that front-end switch and mechanical attenuator is likely faulty. Teardown of the unit reveals significant damage to the attenuator due to some high-power at the input. Unfortunately, this also implies that the front-end RF selector and pre-amplifier modules are also damaged. In the second repair video, the front-end module is disassembled and damage to the dies can be observed.
Luckily, a relatively inexpensive front-end (SSLAM) unit is sourced from eBay and the repair is completed. The performance of the unit is verified after the repair and the front-end I/Q input functionality is demonstrated.