TSP #176 - Teardown, Repair & Analysis of a Rohde & Schwarz AFQ100A I/Q (ARB) Modulation Generator
19.2K views
October 10, 2020 2:12 PM
In this episode Shahriar investigates a failed Rohde & Schwarz AFQ100A I/Q (ARB) Modulation Generator. This instrument provide differential I/Q outputs with exceptional SFDR which makes it ideal for various wireless system testing. The instrument shows a stand-by LED but does not power on.
The problem is tracked to the main power supply’s soft power-on circuit. After the repair of the power supply, it becomes clear that the main HDD is also defective. An identical donor drive is used to repair the broken HDD main controller board. A full teardown of the instrument is also presented. After the repair, the instrument is used to generate various arbitrary waveforms for performance verification.
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TSP #175 (II) - Teardown & Repair of a Fluke 744 Documenting Process Calibrator (Part 2)
15.5K views
September 20, 2020 10:09 PM
In this episode Shahriar return to the repair of the 744 Documenting Process Calibrator. A new firmware has been found and can be uploaded into the instrument. By forcing the processor into a bootloader mode, the firmware update can happen even if the original firmware is corrupted.
After the firmware fix, the instrument is tested for various functionality include DC/AC/I/Resistance calibration and measurement modes.
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TSP #175 (I) - Teardown & Repair of a Fluke 744 Documenting Process Calibrator (Part 1)
18.8K views
September 19, 2020 6:16 PM
In this episode Shahriar attempts to repair a Fluke Documenting Process Calibrator. The device does not power on with neither a battery nor an external power supply. Although the schematic of this particular instrument is not available, an older model schematic shares many of the design aspects.
After close examination of the circuit and various testing of power supply sub-circuit, real-time clock and main processor, it becomes clear that the problem is with a corrupt firmware. The repair is put on hold until a firmware upload method is determined.
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TSP #174 - Teardown, Repair & Analysis of an Agilent 4.5GHz E5071C ENA Vector Network Analyzer
21.7K views
September 13, 2020 9:15 PM
In this episode Shahriar repairs an Agilent E5071C ENA Vector Network Analyzer generously loaned by AllTest. Please visit their website for all your measurement, calibration and service needs:
sales@alltest.net
https://alltestchambers.net
https://alltest.net
The network analyzer is missing the main HDD which initially prevents it from being tested. An image from a donor E5701C instrument is used to boot the unit and gain access to the instrument firmware. The unit shows an inaccurate S11 with an open Port 1 while S22 shows a perfect reflection. This indicates a potential problem with the Port 1 T/R module.
Teardown of the module reveals catastrophic damage to the resistive front-end coupler which has been mostly likely caused by a large RF input power incident. After cleaning the PCB area, a replacement coupler is constructed. The repaired unit is checked for full self-test and used to measure a YIG tuneable filter.
You can may check the Andostar microscope lineup here: (Direct Link / Not-tracked)
https://www.aliexpress.com/store/900802?spm=a2g0o.detail.100005.2.4d4f407ekYxi5H
More information about Wheatstone Bridge:
https://www.mwrf.com/technologies/test-measurement/article/21849280/the-wheatstone-bridge-how-does-it-impact-vna-measurements
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TNP #1 - Teardown & Repair of a Z-Wave GE ZW4005 Home Automation Wall Relay Switch
30.7K views
August 30, 2020 8:48 PM
In this episode Shahriar repairs a faulty Z-Wave ZW4005 wall paddle switch. These devices are used in conjunction with a Zigbee hub for home automation. The failure symptom is a blinking LED indicator light which can sometimes be accompanied with relay clicks.
The teardown shows a switching power supply IC responsible for providing power to the Zigbee module. This switching IC requires external diodes, capacitors and inductors for operation. A failed capacitor on the feedback path has caused a startup failure of the switch. A replacement corrects the problem.
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