In this episode Shahriar repairs an Agilent EPM-441A (E4418A) Power Meter. The unit does not boot and displays “Loading firmware…”. After monitoring internal digital signals, the problem is traced to a faulty SRAM IC. After replacement, the unit completes the boot-up process.
Additionally, the principle operation of power sensors is reviewed including both thermocouple based, as well as diode rectifier based. The block diagram of a USB-based power sensor is examined along with a full teardown of a non-functional power sensor. The detector diode circuitry is examine under a microscope. Finally, the repaired unit is verified for calibration.
In this episode Shahriar completes the repair of the Agilent E3642A power supply with the missing display processor. Thanks to Gerry Sweeney a replacement IC is found and the unit is back to life! Furthermore, the teardown and repair of an Agilent E3620A dual power supply is also shown. The power supply has suffered some liquid damage on several ICs which must be replaced. The PCB has also sustained some damages and has to be repaired. After the rapier, the functionality of the unit is verified.
In order to examine the damage to the ICs from the Agilent E3642A repair, a de-capping process using nitric acid is shown. The VFD controller and two processor with different mask ROM sets are de-capped using this method. The heated nitric acid dissolves the package epoxy revealing the Silicon dies. The dies are then examined under the microscope for comparison and analysis.
In this episode Shahriar takes a look at an Anritsu MS2721A portable spectrum analyzer which does not completely boot up. After displaying the message “Application Running!” the unit no longer advances to the main measurement screen. After intentionally corrupting the firmware, a system menu is observed.
During the teardown of the unit, various DC-DC converters are examined along with a basic overview of the Linear Technologies DC-DC converter datasheet. The main problem is traced to a faulty SRAM IC. After replacing the IC the unit completes the boot process. Various simple experiments are performed to ensure the unit’s functionality and correct operation.
In this episode Shahriar reviews the new Keithley 2460 Source Measure Unit (SMU). The Keithley 2460 shares all the touchscreen GUI advancements of the 2450 SMU and offers up to 100W of power in full four-quadrant operation. The combination of the 2450 and 2460 SMUs from Keithley offer a wide range of applications.
After a brief teardown of the instrument, several experiments are devised to demonstrate the TSP scripting as well as KickStart software capabilities. The experiments include LED failure modes, Geiger counter setup, Op-amp based voltage regulator characterization, temperature controller, non-linear transconductance emulation and data collection application.
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.
The Signal Path (TSP) is an electrical engineering video blog for industry professionals, students and hobbyists. TSP is a non-for-profit website dedicated to provide free education spanning a wide range of electrical engineering topics. Equipment review, tutorials and repair videos are posted regularly.