Measurement & Analysis Instruments

In this episode Shahriar investigates the failure of a Voltech PM3000A 3-Phase Universal Power Analyzer. This instrument is capable of advanced measurements on power profile and performance of a DUT. The unit shows “Voltage & Current OVERLOAD” condition on all channels even without a DUT connected. The teardown of the unit reveals the isolation techniques used between the analog sampling heads and the main digital/DSP board. The instrument uses a combination of transformers and optocouplers to provide power to the sampling heads and receive digitized data from the voltage/current ADCs. Close examination of the unit shows a faulty capacitor on the AC power supply feeding the sampling heads. The capacitor is replaced which corrects the overload condition. The unit is then used to measure the power profile of a simple glue-gun. The PF and THD measurements show that the glue-gun is equipped with a triac for power control; an expected result for a simple glue-gun. Equipment Repair...

In this episode Shahriar takes a look at a malfunctioning Agilent N9020A MXA. This instrument was provided by AllTest who hold the largest inventory of used and refurbished instruments. They have trusted The Signal Path to attempt a repair on the instrument and to support the educational content of this channel. Thank you AllTest! Please visit their website for all your measurement, calibration and service needs: sales@alltest.net https://alltestchambers.net https:/alltest. net The instrument fails RF Alignment despite the fact that all calibration signals are present and can be viewed on the unit. The front-end attenuators also appear to be fully functioning. A full sweep of the input shows that the instrument fails to make measurements between 8. 4GH – 14GHz as well as above 17GHz. The block diagram is analyzed and the likely fault is traced to a doubler circuit on the A13 RF Assembly. The teardown of the assembly along with step-by-step reverse engineering is presented. An X-R...

In this episode Shahriar takes a look at a R&S SMBV100A Vector Signal Generator which does not produce the correct output level. Despite passing all self-tests and ALC checks, the output power level is far below expectation. The output also shows a high-pass frequency response. The (heavily simplified) block diagram of the instrument is examined and discussed. The teardown of the unit reveals the output RF board which is presented in details. Since the instrument cannot detect the failure internally, it is very likely that the fault is part of the RPP output RF relay. The circuitry as well as the datasheet of the components are examined. Measurements show that the output RF relay is never activated due to a faulty PMOS transistor. After transistor is replaced, the unit shows the correct output level. The baseband generator functionality is also verified. You can purchase the Metabo HPT (Hitachi) Cordless Screwdriver Kit from my Amazon Affiliate Link. Equipment Repair, Experim...