Most electronics depend on direct current, or DC-- which is a constant flow of the same amount of energy. So, one way to convert AC power to something closer to DC power is through the use of capacitors. (If you'd like to learn a little more about this, have a look at this video, it's actually quite interesting.) If a capacitor fails, then it just sends through the alternating current and the effect on a set of speakers is a low pitched humming or buzzing sound.
Natalie and I picked up a mid-century coffee table/radio/record player combo a few months ago. When I turned the radio on, it wasn't broken per se, but there was a loud buzzing/humming sound. As I've learned from my research, this is called "the 60hz hum." I may have made up the official phrase, but I think I've earned that authority from what I've accomplished. The electricity from the power lines is delivered in what's called alternating current, or AC-- which, for we non-electricians, means that the electricity looks something like the picture to the right.
Well, you ask, how might one solve this problem, oh wise electronics expert? An anonymous reader shared a bit of his or her expertise in the following comment:
Thank you so much for this information! So I got right on the problem and did a bit more research on my own. First things first, I needed to crack open the ol' radio.
Behold, the much coveted wax tootsie roll (which doesn't sound particularly delicious...)! I've found over the years of trying to fix (i.e. tearing stuff apart) is that you will not learn anything if you're afraid to break it. Step 1 in my case: recklessly take a pair of scissors to the wax tootsie roll.
Continuing to follow the advise from our wonderful reader, I took a gander at the roll and saw 6 bits of important information-- this tootsie roll contains 3 capacitors, all with different ratings. 100MFD, 300VDC on red, 75VDC, 300VDC on blue, and 70MDF, 25VDC on green. uF (which means microfarad... which means...I don't think we need to explore this any further) and MFD mean the same thing and VDC (Voltage Direct Current) and "V" mean the same thing, so if you're looking for new parts, just know those are interchangeable.
So, just search those numbers and you're all set, right? Not quite. Capacitors have a lot of possible values and I wasn't able to find an exact match. Never fear, here is a website that tells you what's an acceptable range for replacement.
So, I then had to wait (very impatiently) for the new parts to arrive. Here is how I waited...
That's right-- we used a whole stick of butter on dinner. It was worth every calorie. Unbelievably good.
Hi, I'm being cute. Can I have some?
He got a little bite from his food bowl. How could we resist? (P.S. How cliché am I? Blog? Check. Pictures of your animal? Check. Captions on photos of your dog with what you think they say? Check. Oh dear, I've become what I hated.)
The new capacitors came in today and I got to work immediately.
Yes. It's sloppy-- even looks like I planted a tiny bomb (aww, cute little guy). I forgot how terrible I am at soldering.
But-- you won't be able to see the sloppy job. Instead, enjoy the beautiful glowing ruby-shaped LED.
It's alive! No more buzz. (Note: See "FM Stereo"? Looks like this puts our unit somewhere around the early 1960's as FM Stereo system wasn't approved by the FCC until 1961)
And now that we're all tuckered out, it's time to get some sleep. We let it all hang out here on Chadwell Drive.