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June 2023 S M T W T F S 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 Meta
Category Archives: DIY
A Surprise in a Re-Stuffed Capacitor
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
Bad Caps in Everything
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 audio precision, capacitors, motherboard, system one, windows 98
3 Comments
Bose® Active Equalizer Test Platform
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 Bose, conversion, Equalizer, sockets, test platform, transistor
3 Comments
Neat Little 60FX5 Stereo Single-Ended Tube Amplifier
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
Building the SSTRAN Part 15 Low Power AM Transmitter Kit
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
Building a Better Voltage Regulator
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 7805, current, diy, heat, lm7805, parts, projects, regulator, switching regulator, voltage, waste
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How to Read Capacitor Codes
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
What do we have here?
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 901, Bose, cosmos industries, direct, direct/reflecting, mystery, mystery speaker, predecessor, prototype, reflected wave, reflecting, series I, speaker, Speakers
2 Comments
Mailbag: What’s the best multitester for vintage radios?
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 chanalyst, multitester, signal tracer, test equipment, vintage radio repair
2 Comments
555 timer teardown (and a Retrovoltage drum trigger project)
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 →