Category Archives: DIY

A Surprise in a Re-Stuffed Capacitor

Posted on October 18, 2016 by jwk

I was recently re-stuffing some capacitors for a radio. It’s not something I do often, but I’ve accumulated a pile of pulled vintage caps over the years so I have some on hand if a customer requests the most detailed … Continue reading →

Posted in DIY, Electronics, Radios and Tubes, Vintage | Tagged , , | 3 Comments

Bad Caps in Everything

Posted on July 20, 2016 by jwk

I just had a bit of a scare with my Audio Precision analyzer. The 2004-era Dell OptiPlex GX270 which drives the AP hardware decided it would refuse to power up – just flashing the “ON” light for a fraction of … Continue reading →

Posted in Computers, DIY, Electronics, Test Equipment | Tagged , , , , | 3 Comments

Mercury Switch Find

Posted on July 5, 2016 by jwk

Digging through a seldom-used parts bin, I made a cool discovery: a set of four mercury switches, still intact: These are used as tilt and vibration sensors in mechanical systems. They’re heavy from the mercury inside, and it sloshes around … Continue reading →

Posted in DIY, Gadgets | Tagged | 3 Comments

AUX in Volvo Stock Head Unit Radios

Posted on June 3, 2016 by jwk

Dangerous Prototypes shares an article detailing how Karl Hagström hacked an aux input to his 2007 Volvo V70 stock stereo. Why, why, why isn’t there an AUX input on my car stereo from 2007? Yes 2007 was before the big … Continue reading →

Posted in Commentary, DIY, Electronics, Gadgets | 1 Comment

Bose® Active Equalizer Test Platform

Posted on April 13, 2016 by jwk

This project is going to take a while since I’m slammed in the shop, but I’m in the process of converting a Bose® 901 Series I Active Equalizer to  a test platform. With sockets for the transistors, and clip connections … Continue reading →

Posted in Audio, Bose, DIY, Electronics, Stereo, Test Equipment | Tagged , , , , , | 3 Comments

Neat Little 60FX5 Stereo Single-Ended Tube Amplifier

Posted on March 6, 2016 by jwk

While digging around, I came across a really simple circuit in the RCA Receiving Tube Manual describing a 1WPC stereo amplifier using only two tubes, the 60FX5 power pentodes, and a single silicon diode. The 60FX5s have high enough gain … Continue reading →

Posted in Audio, DIY, Projects, Stereo | Tagged , , , , , | 5 Comments

555 timer teardown (and a Retrovoltage drum trigger project)

Posted on February 23, 2016 by jwk

Ken Shirriff’s blog has a fantastic and detailed teardown of a 555 timer, the ubiquitous decades-old timer circuit that turns up in so many places: If you’ve played around with electronic circuits, you probably know the 555 timer integrated circuit, … Continue reading →

Posted in Collections, Commentary, DIY, Gadgets | Tagged , , , , , , | 1 Comment

Building the SSTRAN Part 15 Low Power AM Transmitter Kit

Posted on February 21, 2016 by jwk

Have a bunch of old tube radios, but nothing good on the air in your area? That’s a common problem, and SSTRAN has the solution! I just built one of these to give as a gift, and thought I’d write up … Continue reading →

Posted in DIY, Electronics, Projects, Radio | Tagged , , , , | 3 Comments

Building a Better Voltage Regulator

Posted on February 17, 2016 by jwk

Glancing through my feeds, I stumbled across a note on The Paleotechnologist describing a new replacement for the venerable LM7805 linear regulator IC. It turns up in a ton of devices, pretty much anything with a medium-current 5V rail including … Continue reading →

Posted in Collections, DIY, Electronics | Tagged , , , , , , , , , , | Leave a comment

How to Read Capacitor Codes

Posted on January 24, 2016 by jwk

I ended up with a massive stash of mil-spec CDE Mica caps recently, and was searching for a refresher on decoding their military part numbers like “CM05FD221GP3”, since the caps came marked for their values but not their voltage ratings. … Continue reading →

Posted in Commentary, DIY, Electronics | Tagged , | 1 Comment