Kerry D. Wong

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.

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.

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.

A couple of weeks ago, I got myself an Agilent U1731B LCR meter on eBay. These handheld LCR meters are quite expensive when new, but can be found on eBay for a fraction of the original price. Dave Jones at the EEVBlog did a teardown video on a better spec’d U1733C (and U1733B) meter a few years ago, I suspect that circuit-wise the U1731B would be quite similar to what’s inside of a U1733B. Continue reading ‘Agilent U1731B LCR Meter Teardown’ »

Have you ever wondered what is inside of a 15 year old commercial color projector? Well we will find out in this post today. As usual, a video of this teardown is included towards the end of the post. Continue reading ‘Extreme Teardown of a Panasonic PT-L780U 3LCD Projector’ »

I bought a USB wall outlet adapter recently so that I can free up my wall outlets while charging my phones and tablets. Of course, before putting it into use, I wanted to open it up to take a peak inside to see if it was properly engineered and at least to make sure that it would not be a safety hazard at the least. After all, this USB adapter is meant to be plugged in all the time. Continue reading ‘Teardown of an MVMT Dual USB Port Wall Outlet Adapter’ »

Recently I got hold of a dead APC SurgeArrest power strip that was about to be thrown out in my office. The power strip simply doesn’t provide power to any of its outlets regardless of the power switch position. Since there was no external fuse that I could find, I decided to take it apart and find out why and how it had failed. Continue reading ‘Unusual Failure Mode of an APC Surge Protector’ »

I just picked up a Keithley 775A programmable frequency counter from eBay. Specification-wise, this counter is very similar to the Racal Dana 1992 frequency counter I repaired last year. The Keithley 775A I got came with an additional channel (option 7751) and is capable of measuring frequencies up to 1.3 GHz. Continue reading ‘Keithley 775A Programmable Counter Teardown’ »

Although LED light bulbs have been around for a while, I have not been able to totally replace all my lights in the house to LED ones until quite recently. The main reason is that some of my existing light fixtures only take G16.5 style bulbs with E12 screws and higher wattage LED bulbs of this kind only became available until quite recently. Continue reading ‘Teardown of an EcoSmart 60W Dimmable G16.5 LED Bulb’ »

I recently bought an HP 8671A microwave frequency synthesizer on eBay. This synthesizer can generate signals from 2GHz to 6.2GHz with an unleveled output of more than 8dBm. It is a nice complement to my HP 8642B signal generator and Wavetek 907 signal generator. Using these generators, I can now generate signals of pretty much any frequencies under the 12GHz range. A video of this teardown is linked towards the end of this post. Continue reading ‘Teardown of an HP 8671A Microwave Frequency Synthesizer’ »

My video on the teardown of an HP 493A traveling wave tube amplifier had generated quite a bit of interest. After I revealed that the electron gun portion of the tube was radioactive, a couple of my YouTube channel viewers had wondered if I could take the traveling wave tube further apart. So I did just that. Continue reading ‘Further Disassembly of the HP 493A TWT’ »

I few months back, I wrote about my experience with the six dimmable Philips LED bulbs I purchased a year ago. Those light bulbs all failed within months of each other in just over a year of use. This time around though, it’s the Crees ones that had bit the dust. They lasted a few months longer and were among the twelve I originally purchased. So I decided to open up one to see how the Cree LED bulbs were constructed. Continue reading ‘Teardown of a 65W Cree LED Bulb’ »

I recently picked up a BK Precision 1696 programmable switching power supply off eBay. Unlike many of the vintage test equipment I did teardowns with in the past, this model is still in production today. The one I got was sold with a damaged LCD screen and thus I paid very little for it. Of course, a brand new one would cost around $300. Continue reading ‘Teardown of a BK Precision 1696 Programmable Switching Power Supply’ »

The last ingredient for my backup power project is an inverter. Since the battery bank I built is a 12V 1.5kWh one, an inverter that can handle a load between 500W and 1000W would be a suitable choice. In theory, all the lights and the refrigerator in my house consume just around 500W. So the 1.5kWh battery bank should be able to power all the essentials for at least a couple of hours in the event of a power failure. Continue reading ‘Teardown and Testing of an 800W PureSine Inverter’ »

I recently purchased a BSide ACM03 Plus clamp meter so that I could do some high current measurements for my tab welder project. This meter can be bought on eBay for around $25, which makes it one of the cheapest Hall effect clamp meters on the market that is capable of measuring both AC and DC current. Continue reading ‘BSide ACM03 Plus Clamp Meter Review and Teardown’ »