TSP #198 - Teardown, Repair & Analysis of an Anritsu MG3700A 6GHz Vector Signal Generator (Part 1)
22.7K views
August 8, 2021 6:14 PM
In this episode Shahriar attempts to repair an Anritsu MG3700A Vector Signal Generator. The instrument does not fully power on and suffers from several problems. The digital IF board as well as the main computer are presented. The power-on fault is traced to a faulty fuse on the 5V power supply which feeds the main CPU board. A new fuse enables the instrument to fully boot.
The unit also exhibits a failure for all signals above 3GHz. The instrument is equipped with a super hetrodyne mixer board which covers 3GHz – 6GHz output range. This RF board is examined and explored in details alongside the block diagram of the unit. The fault is traced to a unidentifiable component (potentially PIN diode switches). Bypassing these components allows the instrument to generate sufficient power. However, the repair must stop here for now until these parts can be identified.
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TSP #197 - Teardown, Repair & Analysis of a Rohde & Schwarz FSL 9kHz - 6GHz Spectrum Analyzer
50.2K views
July 25, 2021 1:55 PM
In this episode Shahriar investigates a failed R&S FSL Spectrum Analyzer. The instrument shows an unusual spectrum trace and fails a wide range of self-test functions. The LO Unlock failure is likely the most important item to address which can cause a cascade failure of other functions.
The teardown of the instrument shows a single-board RF design. The system architecture is analyzed along with an X-Ray of the main board showing various RF/LO routes and interconnects. The core synthesizer is examined and measured along the signal path to verify the operation of each part. The failure is traced to an open 1-Ohm resistor which feeds the power supply of the divider IC feeding the PFD of the PLL. A ceramic capacitor failure is also observed which may explain the damage to the 1-Ohm resistor. After these components are replaced the instrument passes all self-tests. The functionality of the instrument is verified by measuring tones from 9KHz – 6GHz using a Keysight MXG.
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TSP #196 - Tutorial & Experiments on Tunable Semiconductor Lasers & Wavelength Locking Methods
24.3K views
July 11, 2021 8:55 PM
In this video Shahriar dives into the world of tuneable semiconductor lasers. First, a Santec TSL-200 source is presented and repaired. The performance of the instrument is verified using a multi-wavelength meter. A DFB gold box laser module is then presented along with a demonstration showing the sensitivity of the laser diode to temperature variations. The entire wavelength locking mechanism of the DFB laser is presented in details along with the principle operation of an Etalon wavelength interferometer. The teardown of the module shows all its inner workings.
The LightSquare product and its teardown is also shown which includes a diffraction wavelength measurement system. Finally the operation of the TSL-200 tuneable semiconductor laser is presented which uses a tuneable external cavity Fabry-Perot laser. Finally the teardown of the multi-wavelength meter is shown along with the operation of the Michelson Interferometer inside.
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TSP #195 - Teardown, Repair & Experiments with an Agilent 8163A Lightwave Multimeter & Laser Modules
16.8K views
June 26, 2021 8:22 PM
In this episode Shahriar repairs an Agilent 8163A Lightwave Multimeter. The instrument shows a flickering screen and does not boot. The teardown of the unit is presented along with a general instrument architecture. The power supply is verified for functionality and the instrument simply comes back to life on its own! It most likely has had a poor internal connection which is resolved after reassembly.
Two modules are also presented, a dual-input InGaAs power sensor module as well as a dual Fabry-Perrot laser module. The teardown and analysis of both are presented along with wavelength and spectrum measurements.
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TSP #194 - Teardown, Repair & Experiments with a Marconi 2186 130dB 5GHz Programmable Attenuator
15.3K views
June 13, 2021 9:45 PM
In this episode Shahriar repairs an IFR (Marconi) 5GHz programmable attenuator capable of reaching a maximum of 130dB attenuation in 1dB steps. The Instrument does not power on and a teardown reveals some missing components inside. After replacing the missing component, the instrument powers on but the S-Parameters show that the mechanical attenuators have serious contact problems. Finally after cleaning the attenuator contacts, the instrument is fully operational. The unit is used to measure the performance of the Keysight MXR at very low input signal powers.
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