In this short episode Shahriar investigates the failure cause of a Keithley 2400 SMU. The unit powers on and responds to controls however produces no output signal. Further examination reveals that the VFD display shows no activity when the output is enabled; normally the measured output voltage and current are displayed. This failure points to a digital problem, potentially a failure in the analog board FPGA.

Upon close inspection the FPGA clocking circuitry appears to have a failed solder-joint. A quick re-flow of the affected part corrects the problem and the unit reports the appropriate readings. The unit is then upgraded to the latest firmware and calibrated using a Keithley 7510 DMM.

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In this episode Shahriar reviews the long awaited Keysight MXA Signal Analyzer (N9020B). The new X-Series Spectrum Analyzers from Keysight offer an entirely re-designed GUI interface which supports multiple tabs as well as multi-touch interaction. The review is organized as follows:

1:07 – Model comparison and overview of x-series spectrum analyzers.
7:08 – Instrument physical overview.
11:49 – New GUI overview and demonstrations.
22:44 – Instrument block diagrams and analysis.
28:46 – Brief look inside the MXA spectrum analyzer.
32:53 – Back-scattering communication experiment block diagram and description.
37:16 – Phase noise characterization of doubler and amplifier.
51:54 – Complete back-scattering experiment measurements and analysis.
1:04:45 – Analysis of broadband modulated signals by using the S-Series scope and MXA Signal analyzer at the same time.
1:13:56 – Concluding remarks.

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In this short episode Shahriar repairs a more affordable instrument! This BK Precision LCR meter does not power up despite looking almost new. The teardown of the unit reveals several damaged components. Without any schematic and obscure part numbers some circuit configurations have to be reverse engineered. One of the main failed components is a TI DC-DC converter IC whose datahseet is examined during the repair.

The damaged components are replaced and the unit powers on normally. The performance of the instrument is verified using a HP LCR meter.

The demonstrated Soldering Iron Stand can be found here:
http://goo.gl/FHNJY1

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In this short episode Shahriar takes a close look at a pair of Hewlett Packard microwave electro-mechanical step attenuators operating up to 26.5GHz. Mechanical attenuators offer excellent repeatability, low insertion loss and nearly limitless linearity. The teardown reveals that the construction of both modules is very similar on the microwave path. In fact, the lower-frequency model still uses the same attenuator components. The newer model employs electronic control circuity while the older generation attenuator uses purely mechanically controlled DC path. Both models use a solenoid style actuators for step attenuation control.

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In this short episode Shahriar attempts to revive a high-accuracy decade resistance box using the famous DeoxIT cleaning and restoration products from CAIG Laboratories. The DeoxIT D-Series products are particularly aimed at metal-metal contacts which have suffered oxidization and can provide a low-resistance repeatable contact after application.

The existing decade resistance box shows inconsistent measurements and intermittent contacts prior to the DeoxIT application. After spraying all contacts the instrument is significantly improved with repeatable and accurate resistance measurements. DeoxIT can be purchased from a variety of suppliers and vendors including Amazon.

Check out DeoxIT D-Series:
http://store.caig.com/s.nl/sc.2/category.188/.f

The Signal Path
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