Using software defined radio such as the popular RTL-SDR (1, 2) as a spectrum analyzer is nothing new (examples can be found on HackADay and EDN). In this blog post, we will discuss some of the do’s and don’ts when…
I have been quite happy with my fixed-up Keithley 197 5 ½ digit bench meter purchased from eBay (you can find the teardown pictures here) earlier this year. Keithley 197 has a battery pack option (Model 1978), and this option…
Ever since I got my HP 436A power meter, I have been looking around hoping that I could obtain a compatible power sensor (e.g. 8484A) at a reasonable price to go with it. But these power sensors are quite expensive…
In my last post, I showed my LED backlight mod of the HP 8642B synthesized signal generator. And during the process, I also showed some pictures of the A1 (keyboard and LCD) module and A2 (modulator) module alone with an…
If you take a look at the picture below, you may recognize immediately that it is a picture of an HP 8642B synthesized signal generator. But if you take a closer look, you probably will notice something different if you…
In my last couple of blog posts, I did a brief overview of the EnOcean Pi sensor kit from Newark and demonstrated how to compile and run the example code using a Raspberry Pi. In this blog post, I will…
In my previous post, I took a quick look at the EnOcean sensor kit from Newark for Raspberry Pi and tested its basic functionalities using the Fhem home automation software. In this blog post, I will walk you through the…
I recently got the EnOcean Pi and EnOcean sensor kit from Newark. The sensor kit includes a temperature sensor module (STM330), a magnet contact transmitter module (STM320) and a pushbutton transmitter switch module (PTM210). The EnOcean Pi module is a…
As I mentioned in my previous posting, there was an issue with my Wavetek 907 microwave frequency generator. While everything was fine during my initial testing, the frequency display is now stuck with an out-of-range display and the adjustable frequency…
DS3232 is an extremely accurate RTC with a guaranteed accuracy of 2.5 ppm (0 °C to 40 °C), which translates into an error of just 80 seconds over the course of a year under the worst case scenario. I had…
Last time, I did a teardown of an HP 5350B microwave counter. And as I mentioned in my teardown, the oven-controlled crystal oscillator (OCXO) did not appear to be working as the OVEN indicator would not go off even after…
Here is a teardown you do not see very often. I recently bought an HP 5350B 20 GHz microwave counter off eBay. HP 5350B uses harmonic heterodyne down-conversion technique to convert the microwave frequency into the range of its internal…
I recently bought a few old power transistors from eBay. These are PNP Tung-Sol germanium transistors. According to the date code (6326) these transistors were made back in 1963, long before I was born. The last time I actually used…
A few days ago, I bought a Keithley 197 sold as “unknown working condition” on the cheap. The seller said that some of the keys on the meter were unresponsive. I figured that I’d try fixing it if I could.…
A while ago, I did a tear-down of a Keithley 196 bench multimeter. Towards the end of that post I showed a picture of my breadboard setup for backing up the firmware EPROM (27128) in case I needed to re-flash…