Teardown of a Cel-Fi Go X Cell Signal Booster

In the area where I live, the cell phone reception is spotty at the best. Even though I am only a couple of miles from a nearest tower, I barely get any cell signal at all let along usable 4G coverage. Since nowadays everyone is working from home, I thought it would be a good investment for a cell signal booster so that in the event I loose my network connection I can continue working tethered to my phone.


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Non-destructive Testing of Fuses

A fuse is a sacrificial device for the protection the rest of the circuit in an over-current situation. There are situations we need to know with some reasonable confidence what the actual maximum current is for a given fuse without destroying it. This is beneficial when the specifications for the fuse at hand is unknown (e.g. with cheap no-name brand fuse), or the circuitry to be protected is so critical that the interrupt current level must be specified precisely.


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Making an OBD-II Solar Trickle Charger

I have been travelling quite a bit for the last year or so and have not been able to drive my car as frequently as I would have liked. As a result, I often left my car at the airport parking lot for a week at a time. This is not great for modern cars since many electronics continue to draw power even when the car is turned off. The stand-by current draw can be quite significant depending on the type of electronics the vehicle has. This constant current draw along with lead-acid battery’s relatively high self-discharging rate create a perfect recipe for a drained battery if the car is left parked for some prolonged period of time.


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Teardown of an Amrel PPS 35-2 Programmable Power Supply

A while back, I did a teardown on a dual-channel Amrel PPS-2322 programmable power supply, and was quite impressed by its solid construction. Recently, I found another Amrel power supply on eBay and this time it is a single channel version (PPS 35-2). Let’s take a look inside this signal channel version and see how much in common it has compared to the dual channel 2322.


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Teardown of a Keithley 230 Programmable Four-Quadrant Voltage Source

The latest addition to my lab equipment is a Keithley 230 programmable voltage source which can output up to ±100V. Unlike many of the power supplies and voltage sources I have, the Keithley 230 is capable of operating in all four quadrants, meaning it can both source and sink current in either of the output polarities. Although the current capability is limited to ±100mA.


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Teardown of a Microwave I/Q Down Converter

I recently picked up a downconverter box on eBay. My original plan was to use the enclosure for another project as it has a very nice aluminum enclosure. Naturally of course, I wanted to take a look at what kind of downconverter this one is and how it works first.


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Teardown and Modification of an Electrophoresis Power Supply

Electrophoresis power supplies are commonly found in biology and other life sciences laboratories. These power supplies are usually capable of supplying high voltages and high currents required for gel electrophoresis–a method used for separating DNA, RNA and other protein fragments based on their size and charge. There are many used electrophoresis power supplies out there in the second hand market and can be bought quite cheaply. I am curious whether these electrophoresis power supplies are suitable for electronics lab use as a lab grade high voltage power supply can be quite expensive. So I recently picked up one from eBay to take a look.


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Teardown of a Marconi 2305 Modulation Meter

I picked up a Marconi 2305 modulation meter off eBay the other day. As the name indicated, a modulation meter is used to measure the modulation characteristics of a source signal. The Marconi 2305 is capable of measuring amplitude/frequency and phase modulated signals from a few hundred kHz all the way up to 2 GHz.


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LogiMetrics A300/S 2 – 4 GHz Traveling Wave Tube Amplifier – Repaired

In my previous blog posting, I did a teardown of a LogiMetrics A300/S 2 to 4 GHz Traveling Wave Tube Amplifier (TWTA). After doing the teardown, my focus immediately turned to troubleshooting the unit and hopefully restoring the unit back into working order again.


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Teardown of a LogiMetrics A300/S Traveling Wave Tube Amplifier

I just picked up a LogiMetrics A300/S 2 GHz to 4 GHz (S band) traveling wave tube amplifier (TWTA) on eBay. I had done an extreme teardown of an HP 493A TWTA a while ago and it was quite fascinating to see what’s inside of a TWT. This LogiMetrics A300/S was made from the late 70’s and unlike the HP 493A it was made entirely using solid state devices (e.g. transistors and ICs), the TWT itself of course remains a vacuum tube.

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Teardown of a Spex HS1000 Monochromator Controller

Monochromator is one of those things that has always fascinated me. Over the years, I have done quite a few experiments (I, II, III) with an EP200Mmd monochromator and it was a lot of fun. Because monochromators are such highly specialized equipment, decent ones are hard to come by at reasonable prices second hand. So my strategy has been to scour eBay once a while and pick up bit and pieces whenever I can.


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Experiments with a Hydrogen Thyratron

I was doing some experiments which involves switching high voltages (>3 kV) under high current (>30 Amps) load. Although solid state devices such as SCRs (Silicon Controlled Rectifier, or Thyristor) or IGBTs are the ideal candidates for this kind of operations, the prices for these devices are through the roof (1, 2) when the breakdown voltage exceeds the 3kV threshold. I did have a couple of QIS6502002 6500V 25A IGBTs I bought on eBay many years ago but as it turned out they were quite fragile, a few minor overloads during my experiments was enough to destroy them unfortunately.


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Teardown of a Piezoelectric Vibrating Gyroscope

Gyroscopes nowadays are based on micro-electro-mechanical systems (MEMS) technology. They are low cost and extremely miniaturized. A device combing both a three-axis gyroscope and a three-axis accelerometers (sometimes these devices are referred to as 6DOF devices) such as the MPU-6500 for example can be had in a QFN package as small as 3 mm x 3 mm and under 1 mm in height. Before these MEMS devices gained mainstream popularity however, larger piezoelectric vibrating gyroscopes were used in many consumer electronics devices.


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PLA Dielectric Strength Measurement

In my previous post, I designed and 3D printed a high voltage connector for my Bertan 225-20R high voltage power supply. The silicone high voltage wire I ordered had finally arrived so I made a couple of cables using the connectors I printed. A few of my viewers had questioned the suitability of using PLA as printing material in high voltage applications so I decided to measure the dielectric breakdown voltage of PLA and gather some real-world data.
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3D Print an HV Connector

In one of my previous posts, I did a teardown of a Bertan 225-20R high voltage power supply, which is capable of outputting 1mA with an adjustable voltage range up to 20 kV. The power supply came with a special high-voltage connector however (similar to the CMC series connectors from Connectronics Corp), but I wasn’t able to get a mating connection cable. At least not at a reasonable price.
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