In my last post, I did a teardown of the Keithley 775A programmable counter/timer. And while feeding a 10 MHz signal from my Rubidium frequency standard, I noticed that the measured frequency was significantly lower (9.9981 MHz) than the nominal…
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…
There are a lot of cheap electromagnetic radiation testers out there which boast some quite impressive claims. So I decided to pick up a popular one (GM3120) from eBay to see how well it works. And perhaps more importantly, I…
While I was making a video on how to use HP 8671A as the frequency reference for an improved version of my simple DIY tracking generator for my HP 8566B spectrum analyzer, my spectrum analyzer suddenly decided to call it…
I recently received an M5Stack ESP32 development kit from Banggood. Although I have not used any ESP32 based development boards before, I have heard many good things about the ESP32 platform, especially for its rich feature set and versatile connectivity.…
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…
Differential amplifiers come in handy in applications where common-mode noise and interference are present in the system. This is largely attributed to the very high common-mode rejection ratio (CMRR) these amplifiers provide. And because of the high CMMR they are…
In my previous post, I did a teardown of an HP 8620C sweep generator along with an HP 86245A 5.9 GHz to 12.4 GHz RF plugin. A few of the plguin boards in the 8620C had leaked capacitors and also…
I just picked up an HP 8620C sweep oscillator with an HP 86245A 5.9 GHz to 12.4 GHz RF plugin on eBay. This time around though, the unit does not work. While it was advertised as a working unit I…
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…
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…
In my previous video featured on EEVBlog I did a teardown of an HP 493A microwave amplifier along with the traveling wave tube inside. I actually had done a teardown of an identical unit a while ago but this time…
Big thanks to Dave Jones at the EEVBlog for featuring one of my teardown videos. His generosity would certainly help smaller channels like mine attracting more viewers.
Quite a few people had contacted me on the availability of the firmware for the Amrel PPS-2322 programmable power supply I did a teardown with a few years ago. I finally got a chance to it and backed it up…
As I mentioned in one of my posts a few years back, a color analyzer from the 80’s can be a treasure trove for the hobbyists. And at the very least, it is a cheap way to get yourself a…