Choosing electrolytic caps for vintage audio gear and when to change all - Page 1
Forum section: electronics / beginners

author: RiRaRi
author_rank: Regular Contributor
timestamp: February 25, 2025, 05:12:15 pm
content: Hello. I am repairing boomboxes and audio gear from 70s and 80s. Mostly they only have dirty controls and bad cassette belts but sometimes there is a faulty electrolytic capacitor. The one boombox i am currently repairing has all capacitors in excellent condition (good capacitance, low ESR) but one which i replaced. Should i change all e caps just to make sure there will be no issue with them in the future since one went bad? Also, more importantly: what caps to buy from best brands like Nichikon, Rubycon, Panasonic etc. What series to choose from? Should i pick different ones for tuner section and different for amplifier stage? And, last question: will i need to tune the radio after replacing e caps in tuner section if they are replaced with same ones (except ESR). Thank you all for help!

author: Addicted2AnalogTek
author_rank: Frequent Contributor
timestamp: February 25, 2025, 05:33:20 pm
content: Whether to replace or not to replace all (even the good ones) electrolytic capacitors in a device is going to be a matter of preference, as well as a touchy subject for people who restore vintage electronics. You're going to get lots of differing opinions.My personal advice is to start out by only replacing failed capacitors that you find. Take careful note of what manufacturer, series, date code, and type of capacitors you find that have failed, and base your future decisions regarding the replacement of still-good capacitors off of that information. Also, as you search online repair information for each piece of gear you are repairing, you will find out what parts are "failure prone" and should be replaced while you have access to them.As far as replacement parts selection, there's loads of useful information on this forum and on people's personal repair websites. For starters, in the forum section here, under "Electronics", click on "Repair" and read over the pinned topics.

author: CaptDon
author_rank: Super Contributor
timestamp: February 26, 2025, 01:46:01 pm
content: I found in our broadcast audio equipment made from the late 70's up in to the 90's that if the had the axial lead Sprague electrolytics they were indeed failing. Everything from the 10uf@16v up to their power filter caps like 2200uf@50vdc. I found the same in Tektronix gear. If it is Sprague, electrolytic and old it's bad! We finally went through all of our ITC and BE broadcast cart decks and shotgunned every Sprague in them. Best move for reliability we ever did!!

author: Addicted2AnalogTek
author_rank: Frequent Contributor
timestamp: February 26, 2025, 02:50:33 pm
content: Quote from: CaptDon on February 26, 2025, 01:46:01 pmThat's interesting. I'm curious if Sprague manufactured capacitors in Europe & Asia as well as the U.S. I find a lot of sprague 30D capacitors in vintage Tektronix equipment, but they are rarely bad. Every now and then I'll find one that has failed spectacularly, like the one that exploded inside of my 067-0502-01 Tektronix amplitude calibrator. Usually the culprits are the colorful tantalum capacitors and Mallory branded filter capacitors. In 1980's and 1990's electronics, the "big fail" brand seems to be Matsushita brand capacitors. Then, of course, there's all of the "cheaper option" brand capacitors and voltage under-rated capacitors that fail. There's also the well documented Sprague paper capacitor failures in vintage tube-era equipment, but I don't typically work on that stuff.

author: RiRaRi
author_rank: Regular Contributor
timestamp: February 26, 2025, 07:21:11 pm
content: Which e-caps are you using for vintage audio gear, good brand and series? Is it okay to use same ones in amplifier and tuner stage?