Category Archives: Electronics

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 →

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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

Philips High Fidelity Laboratories 673 Tuner Repair and Alignment

Posted on January 4, 2016 by jwk

This Philips 673 tuner just came through the shop for an overhaul and adjustment. It was working for the most part but the alignment had shifted and there was room for improvement on the sound quality. Philips designed this tuner … Continue reading →

Posted in Audio, Electronics, Radio, Vintage | Tagged , , , | 3 Comments

HH Scott 233 Stereo Integrated Amplifier Overhaul

Posted on December 31, 2015 by jwk

I was lucky enough to get to work on a very nice Scott 233 stereo integrated amplifier. This example was wonderfully well preserved, coming out of a storage unit looking like it had just left the showroom floor. Unfortunately, though, … Continue reading →

Posted in Audio, Electronics, Radios and Tubes, Stereo, Vintage | Tagged , , , , , , | 7 Comments

What do we have here?

Posted on December 1, 2015 by jwk

I was reading about how to build a capacitor checker from the December 1959 issue of Popular Electronics and stumbled across something that looked very familiar. I know that shape. Nearly identical to a Bose® 901 Series I/II cabinet, and even … Continue reading →

Posted in Audio, Bose, Collections, Commentary, DIY, Electronics, Vintage | Tagged , , , , , , , , , , , , , | 2 Comments

Bose® 402E Active Equalizer #102853 Repaired

Posted on November 30, 2015 by jwk

The first Bose® 402E Active Equalizer, for the Panaray speaker system, just came through the shop. It’s a small speaker array system, designed around similar drivers in the 901, and uses an Active Equalizer for the same effect. They’re designed … Continue reading →

Posted in Audio, Bose, Electronics, Projects | Tagged , , , , , , , , | 7 Comments

Harman-Kardon Festival D-1000 Tube Receiver Repair

Posted on November 17, 2015 by jwk

All vintage gear has a story to tell, but something really rare and interesting recently came across the bench: the Harman-Kardon Festival D-1000. While it looks somewhat unassuming, a fairly straightforward 15-tube receiver with push-pull 6L6GC outputs and an AM … Continue reading →

Posted in Audio, Electronics, Hi-Fi, Vintage | Tagged , , , | 4 Comments

Harman-Kardon Citation 11 Pre-Amp Overhaul

Posted on November 11, 2015 by jwk

A neighbor brought me his brother’s Citation 11 for a full overhaul. After a few decades of faithful stereo reproduction, then a number of years in storage, it was time for an overhaul to get it working good as new again! Of … Continue reading →

Posted in Audio, Electronics, Projects, Stereo, Vintage | Tagged , , , , | 15 Comments

Mailbag: What’s the best multitester for vintage radios?

Posted on November 2, 2015 by jwk

I recently got this question in the mailbag, and it seemed like a good one to answer: What’s the best multitester for vintage radio repair? That’s actually a tougher question than it seems. The short answer? Well…it depends a bit, but … Continue reading →

Posted in Commentary, DIY, Electronics, Gadgets, Test Equipment | Tagged , , , , | 2 Comments

Antenna Distribution for AM Radios

Posted on October 24, 2015 by jwk

I’ve had a few questions come my way about antenna distribution systems for AM radios, specifically to connect something like a large attic antenna to multiple radios at once. There’s a lot out there designed for VHF/UHF or CATV signals, … Continue reading →

Posted in DIY, Electronics, Gadgets, Radio, Resources | Tagged , , , , , , , , | 9 Comments