No. Let’s dig into this.

I’ll cut to the chase: people don’t know what they don’t know. As long as expert sources of information and professionals are sought when needed, this generally isn’t a problem, but often, they aren’t. With that in mind, I’m going to help with this one, but before we proceed, note that DIY electronic equipment repair attempts significantly increase:

1. The risk of equipment damage
2. The risk of the introduction of new faults
3. The risk of personal harm through electrocution

Stay safe, and if in doubt, take your equipment to a professional.

Dunning-Kruger

The Dunning-Kruger effect describes people overestimating their understanding of topics they know little about. The problem is real, leading to people treating cancer with fruit juice, launching themselves in rockets, denying the moon landings and visiting the Titanic in home-made submersibles.

Dunning-Kruger has also led to an explosion of ‘recappers’ and poorly skilled ‘repairers’, and a ton of damaged and destroyed hi-fi equipment. It’s silly and wasteful, and you should know this: One cannot know much about anything after a few minutes of reading, especially when your sources are others affected by this ‘problem’!

An Example

Capacitors are a generally poorly understood topic, and a reader’s comment on an article I wrote about the Kenwood KD-500 turntable prompted me to write this FAQ. Mark wrote:

A simple fix can be changing any electrolytic caps.. Always good to remove then [sic] and check there [sic] capacitance. 10% below should be changed.

Mark

Grammar aside, the danger lies in what is not understood or said. Mark has likely not owned or repaired a KD-500, and the incorrect advice he’s offering here will not only not help the original enquirer fix his turntable, but will likely lead to him damaging it. You’ll see the silliness of all of that.

Capacitors should be removed and tested, yes, but ESR, leakage and C are all important. Do the people reading Mark’s advice know or understand how to measure that? Capacitors are rarely responsible for speed issues with these decks, something that, again, I think Mark and the people reading comments like these simply will not know.

The biggest issue is the damage DIY-ing can inflict on gear. DIYers typically lack the test equipment, rework tools, knowledge and skill needed to take on this sort of work and often damage or even destroy equipment. This isn’t a judgement BTW, even some repairers can barely solder, so imagine folks who’ve never soldered before, using cheap soldering equipment.

Put all of this together, and you have a recipe for my general annoyance with the misinformation so commonplace in this and other technical spaces.

My reply:

Thanks for your comment, Mark. I appreciate trying to assist others, but given that your comment highlights general misinformation regarding technical electronics repair and only encourages capacitor replacement rather than finding and fixing the issues, it’s helpful if I explain why.

Capacitors are much maligned and poorly understood. Capacitors should be checked, but rarely cause speed issues with these decks. New caps are typically specified to be within +/- 20% of rated capacitance, like these excellent Panasonic parts: https://industrial.panasonic.com/cdbs/www-data/pdf/RDF0000/ABA0000C1209.pdf.

A reading within +/- 20% is within new part specs and measurement error. Replacing capacitors that measure within 10% of spec is not only a waste of time and money, but it will not fix anything unless those parts also have a measurably very high ESR.

Most end-users also don’t have the test equipment needed to make these measurements accurately, nor the experience to interpret the results and therefore should not remove or change parts they cannot properly measure and assess.

Liquid Mike

Facts (Useful)

I’ve provided a few facts here to help readers, from a specialist’s perspective, and as a science educator with an honours degree in science. The internet is an echo chamber for misinformation. Our advisory service and this website proudly combat this problem.

Are capacitors important? Sure. Should all capacitors measuring “10% below” be replaced? No. Did you know that brand-new capacitors typically test low for C, often more than 10% low? There’s nothing wrong with them; they need to reform. Did you know the average cheap multimeter cannot properly test for capacitance, ESR or leakage?

Capacitors can fail and must be replaced when they do. They can also be replaced to significantly improve performance, depending on their role in a circuit. However, a 10% variance from the rated spec does not constitute failure and is within the margin of measurement error of the test gear most owners will have access to.

Summary

All too often, people bin good parts and replace them with inferior parts, trying to solve problems not caused by those parts. There is so much nonsense advice offered about replacing every capacitor after a certain age, but I can assure readers that no truly informed specialist would ever recommend this.

Anyone doing so knows too little to be helpful but enough to be dangerous, and is probably selling parts. One self-described ‘technician’ sells kits on eBay, no surprises here. No self-respecting technician sells, uses or recommends kits.

ESR is a more important parameter than C in terms of capacitor health. Proper lab-grade test and measurement equipment is needed to effectively test capacitor parameters; cheap multimeters cannot do it, and most people do not own expensive test and measurement equipment.

Replacing parts often causes circuit board damage and introduces new faults when done by inexperienced folks with poor rework skills and tools. The best way to save and rejuventate equipment is to have an expert do it, someone with hopefully a decade or three of best practice behind them.