Category Archives: DIY

Retrovoltage Workbench Through The Years

Posted on November 7, 2026 by retrovoltage

A visual history of the Retrovoltage workbench, from 2009 through today, while we wait for a few projects to wrap up. Continue reading →

Posted in Collections, Commentary, DIY, Electronics, Gadgets, Hardware, Ideas, Test Equipment | 1 Comment

Old Crock-Pot Slow Cooker Repair

Posted on November 1, 2026 by retrovoltage

Fixing an old Crock-Pot slow cooker which had become unreliable. Turns out the only electrolytic capacitor in the whole appliance, on the control board, was on the way out and was leaking and losing capacitance. A new one swapped right in, and after a test run, everything seems good as new. Continue reading →

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Everything to Know about Bose 901 Series V Active Equalizer and Speaker Repair

Posted on October 12, 2026 by retrovoltage

A detailed look at the Bose 901 Series V speaker system and Active Equalizer, with a brief history, plus repair tips and tricks, schematics, equalizer curves, and a parts list with direct links to buy what you need. Continue reading →

Posted in Audio, Bose, DIY, Electronics, Hi-Fi, Stereo, Vintage | Tagged , , , , , , , , , , , , | 2 Comments

Everything to Know about the Bose 901 Series IV Speakers & Active Equalizer Repair

Posted on August 10, 2026 by retrovoltage

A detailed look at the Bose 901 Series IV speaker system and Active Equalizer, with a brief history and explanation, plus repair tips and tricks, schematics, a discussion of the 5 different Active Equalizer versions for this generation, and a parts list with direct links to buy. Continue reading →

Posted in Audio, Bose, DIY, Electronics, Hi-Fi, Stereo, Vintage | Tagged , , , , , , , , , , , | 5 Comments

A Surprise in a Re-Stuffed Capacitor

Posted on October 18, 2016 by retrovoltage

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 retrovoltage

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

Bose® Active Equalizer Test Platform

Posted on April 13, 2016 by retrovoltage

Looking for the latest info on repairing your Bose 901 Series I, Series II, or Bose 800 Active Equalizer and speaker system? Take a look at the latest in-depth guide with everything you need to know (and more!) This project … 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 retrovoltage

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 retrovoltage

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 retrovoltage

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