In this episode Shahriar investigates the cause of failure of a Keithley 220 Programmable Current Source. Despite being manufactured in the mid-1980’s, the Keithley 220 is still a very popular programmable current source. Alongside the repair efforts, the schematic of various analog, digital and power supply boards are also presented. By interpreting the failure mechanism, the fault is traced and corrected. The Keithley 220 is then calibrated and the calibration procedure of the sub-100nA range is explained. Finally, the performance of the calibrated unit is verified using a Rigol DM3068 Multimeter.
Archive for November 26, 2012
In this episode Shahriar goes through the teardown and repair process of a Fluke 196B Handheld ScopeMeter. This unit, which has been purchased as a “dead” unit from eBay, is examined for faults. During the teardown, various PCB components, architecture and design is presented. The performance and functionality of the unit is verified with a few brief experiments. Finally, the schematic and block diagram of the Fluke 196B is explored for the finer details of its design and operation.
In this episode Shahriar extensively reviews the Rigol DSA1030A-TG3 Spectrum Analyzer. A wide variety of experiments are performed using the Rigol spectrum analyzer to serve both as a tutorial to use the instrument and to demonstrate its capabilities. Some measurement results are also performed using other calibrated instruments to verify the accuracy of the spectrum analyzer. The Rigol DSA1030A-TG3 can be purchased directly from Rigol Inc.
The following experiments are performed:
1) Signal amplitude, frequency and phase-noise measurements.
2) Low amplitude signal measurements (< -130dBm).
3) Low frequency measurement capabilities (< 9kHz).
4) PRBS length calculations and characterization.
5) Wireless 2.5GHz FM signal transmission and demodulation.
6) Attenuator and band-pass filter response measurements.
7) Amplifier bandwidth and output compression measurements.
8) Calibration and measurements of VSWR using the tracking generator.
9) Characterization of the tracking generator signal quality.