TNP #41 - Stanford Research SR620 Universal Time Interval Counter Teardown, Repair & Experiments
21.9K views
November 17, 2023 1:09 PM
In this episode Shahriar repairs an SRS SR620 frequency interval counter where the magic smoke has escaped! The instrument does not power on and the teardown reveals a burnt resistor. The circuit examination shows a voltage regular for the 5V output which has a short circuit the the chassis. A simple repair and resistor replacement brings the unit back to life.
The performance of the internal OCXO is measured against a Rubidium oscillator and the unit is frequency calibrated. The XY output mode of the unit as well as its ability to measure propagation delays are also shown.
Please consider supporting The Signal Path:
https://www.TheSignalPath.com/Donate
https://www.Patreon.com/TheSignalPath
Other links:
https://www.TheSignalPath.com
https://www.Twitter.com/TheSignalPath
TNP #40 - Stanford Research FS735 Dual Distribution Amplifier Teardown, Repair & Experiments
18K views
November 12, 2023 9:52 PM
In this episode Shahriar repairs a fault SRS FS735 dual distribution amplifier. These instruments provide two independent 7-channel 10MHz distribution modules with exceptional signal purity and isolation. The instrument does not properly powers on which points to a potential problem with the internal power supply.
The unit has two identical power supplies; one for each module. Both power supplies have a failed startup capacitor which can be easily replaced. After the repair, the power supplies are verified for functionality and power delivery. The schematic of the entire unit is described as well as a view of the module PCB. The performance of the unit across frequency, harmonic distortion as well as isolation behavior is also measured and verified.
Please consider supporting The Signal Path:
https://www.TheSignalPath.com/Donate
https://www.Patreon.com/TheSignalPath
Other links:
https://www.TheSignalPath.com
https://www.Twitter.com/TheSignalPath
TSP #234 - QuantAsylum QA403 24-bit, 0.0001% THD Audio Analyzer Review, Teardown & Experiments
37.7K views
October 29, 2023 8:16 AM
In this episode Shahriar takes a detailed look at the QuantAsylum QA403 24-bit, extraordinary linear & low-noise audio analyzer. This low-cost instrument provides the means to test a wide range devices in the audio frequency range:
https://quantasylum.com/collections/frontpage/products/qa403-audio-analyzer
The review of the instrument is organized as follows:
00:00 – Introduction, instrument interfaces and overview
01:03 – Detailed teardown, architecture overview, ADC, DAC, amplifiers, attenuators and interface challenges; isolated properties, THD and SNR considerations
10:14 – Instrument extreme performance verification through loop-back; detailed GUI overview, ADC & DAC operations, attenuators, THD measurements, built-in generators and measurement functions
22:47 – Stanford Research Systems (SRS) DS360 Ultra Low Distortion Generator performance verification using the QA403
25:28 – Characterization of the SRS SR560 Low-Noise Preamplifier, linearity, THD+N, low-pass and high-pass filters responses, low-noise versus dynamic reserve measurements, automated sweeps
35:40 – Characterization of a two-stage audio amplifier and headphone driver module; gain and THD variation measurements as a function of frequency
38:55 – QuantAsylum family of products, example measurements and additional resources
39:27 – Concluding remarks
Please consider supporting The Signal Path:
https://www.TheSignalPath.com/Donate
https://www.Patreon.com/TheSignalPath
Other links:
https://www.TheSignalPath.com
https://www.Twitter.com/TheSignalPath
TSP #233 - How good is an $85, 10GHz Power Sensor? Detailed Teardown, Analysis & Experiments
35.4K views
October 14, 2023 7:22 PM
In this episode Shahriar takes a look at an inexpensive power sensor module with built-in battery and a tiny LCD screen. The instrument claims a large dynamic range of -60dBm to +30dBm!
A leaky internal battery prevents the unit form powering on initially. After analysis of the chemical leakage (using an Agilent Resolve Raman) as well as repair of the battery, the unit return to normal operation. A detailed teardown of the sensor is presented along with the theory of operation for the front-end RF circuits and sub-components. The unit is then measured against a R&S 3-Diode Path NRP power sensor. Although it does not perform nearly as well, it can be used within +/-2dBm accuracy. The unit is then measured against its highest claimed frequency of operation and input power.
Please consider supporting The Signal Path:
https://www.TheSignalPath.com/Donate
https://www.Patreon.com/TheSignalPath
Other links:
https://www.TheSignalPath.com
https://www.Twitter.com/TheSignalPath
TNP #39 - Faxitron MX-20 Digital Micro-Focus X-Ray Machine Teardown, Repair & Experiments
27.9K views
September 17, 2023 3:16 PM
In this episode Shahriar repairs his Faxitron MX-20 digital x-ray system. Although the machine has been producing beautiful images for years, recently it has been outputting out-of-focus images intermittently.
The principle of x-ray focusing and beam-spot generation is presented along with potential electronic methods of achieving focus. The teardown of the unit reveals the main x-ray tube controller PCB which houses the focus control high-voltage modules. Since the problem is intermittent, a reed switch is also suspected. The high-voltage module is measured and appears fully functional. Replacing the reed switch corrects the out-of-focus images. Several x-ray images showcases the sharpness of the unit after the repair.
Please consider supporting The Signal Path:
https://www.TheSignalPath.com/Donate
https://www.Patreon.com/TheSignalPath
Other links:
https://www.TheSignalPath.com
https://www.Twitter.com/TheSignalPath
