In this episode Shahriar "repairs" an HP/Agilent 4349B 4-channel high-resistance meter capable of measuring up to 10^15 Ohms! The instrument has four independent channels and requires an external power supply for measurements.
The instrument does not boot, but unplugging and re-plugging the cables fixes this issue. After some analysis of the theory of operation, a 1G-Ohm resistor is used for performance verification. The resistor is also measured against the Keysight & Keithley 8.5-digit/7.5-digit multimeters as well as the Keithley 2470 1000V SMU.
In this Episode Shahriar attempts to answer a fundamental scientific question, within the budget of The Signal Path. In this case, the question that has confounded scientists since the invention of LEDs: How many LEDs can you light up using a hot dog?!
In this episode Shahriar reviews the successor to the popular Signal-Hound SM200C, the SM435C Real-Time Spectrum Analyzer covering 100kHz – 43.5GHz with 160MHz of gapless I/Q steaming using a 10GbE optical interface.
With its constantly improving Spike software and incredible 1THz/s sweep rate, the SM435C has the potential to be a dream software-defined radio as well as a powerful laboratory & field instrument. This detailed review is organized as follows:
00:00 – Introduction
01:47 – Instrument overview & design
03:49 – Teardown, detailed circuits & systems overview and analysis including X-Ray imaging
16:33 – Analysis of a 24GHz pulsed radar module, real-time capability, zero-span mode, fast sweeps
29:06 – Noise figure personality and noise-figure measurements features
33:40 – Phase noise personality and characterizing the internal instrument phase-noise
35:49 – mm-Wave transmit mixer characteristics, digital demodulation capabilities
39:05 – Wideband IF output for digital demodulation using a Keysight MXR & PathWave VSA
41:35 – Wideband IF output for rapid pulse hopping analysis using a Tektronix MSO-6B Series
45:06 – Additional Spike software features
46:11 – Concluding remarks
In this episode Shahriar repairs another high-voltage Tektronix probe, this time a THDP0100 which is capable of measuring 6kV signals up to 100MHz. The probe does not get detected by the scope. However, it soon becomes clear that the problem with this probe is much more involved than the previous repair.
The probe has a short-circuit inside the probe body as well as several damaged components. Each is replaced one step at a time until a final fault is also detected in the probe head. After the repair, the probe is zeroed, calibrated and used to measure a signal at 6kVpp using an Associated Research HYPOT tester.
In this episode Shahriar takes a look at a non-functional Fluke 5450A resistance calibrator box. The unit is equipped with a wide range of resistors ranging from 1-Ohm to 100-MOhm some of which are 0.005% tolerance. The instrument powers on and shows a single LED on the front panel without any other activity.
Upon further inspection it becomes clear that there are no other activities from the main CPU despite the clock signal being present. A replacement CPU returns the unit to normal front-panel operation. The analog board also has two blown fuses which may be the result of a in-rush event. After fuse replacement the analog relay arrays also function. The unit is measured against a Keysight 3458A 8.5-digit multimeter and shows remarkable accuracy despite its age.
The Signal Path (TSP) is a science & electrical engineering video blog for industry professionals, researchers & students. TSP is a not-for-profit website dedicated to provide free education spanning a wide range of electrical engineering & science topics. Equipment reviews, tutorials and repair videos are posted regularly.
