I have an expensive Fluke meter with a vacuum fluorescent display. The display will slowly dim to the point where it is unreadable, at which time I give the meter a short, sharp shock with my hand, and it brightens back up for a while. I’ve taken the thing apart, and poked and prodded inside, but I can’t find the loose connection. So, I just use percussive maintenance and it works fine…
I’m a big fan of smacking things. Either it fixes the problem or it makes things bad enough that you now have an excuse to get something that really works. 
I had an old Nissan that would stop running on very hot days sometimes. The problem was a sticky fuel pump that could be fixed with a level 12 kick to the front fight panel. (not sure if that counts for an electronic problem?)
LCD monitor on my computer responds to various levels of percussive maintenance. I generally use a rolled up magazine as I started bruising my hand when the percussion level went too high.
On a related (or not so related) note, I had a co-worker whose computer would just up and die every so often – sometimes hang, sometime refuse to power up, all kinds of weird effects (it was just her - like some sort of anti-computer field around her). So, being the computer geek in the office I would get to fix it. My favorite method was slowly moving my hand over the computer in a circular motion about 6 inches from the box as if I was magically recharging the box. Then I’d reboot it and it would work fine. Freaked her out a bit. I thought it was tremendously hilarious.
But, I am definitely a fan of percussive maintenance. Usually the first thing I do to any recalcitrant equipment, whether electronic or not.
Hyperdrive control panels
Yep!
Along the same lines, I used to fly a de Havilland Tiger Moth that would get a stuck impulse magneto when it was hot. The impulse mag provides the spark for starting and without it I couldn’t get the engine started. We had a “special tool” that we used to give the mag a good solid WACK. You knew you’d done it right when you heard a CLUNK after you hit it.
Same manufacturer* but a bit more modern, I now fly a de Havilland Dash 8. Some of ours are fitted with long range fuel tanks in the passenger cabin. The tanks have a float gauge that gives either a FULL or EMPTY indication on an advisory light in the cockpit. Part of the pre-fuelling check is to make sure the automatic fuel shutoff works. This is done by simulating a full tank by sending the float gauge to the top where it should give a FULL indication and the fuel should be automatically shut off. If this is successful we can fill the tanks properly. Sometimes the float sticks at the top of the tank and the FULL indication doesn’t go away meaning we can’t fuel the tank because it’s in automatic shutoff mode. A good solid WACK! to the top of the tank fixes the problem.
*Not really, but near enough.
I own a pocket calculator that usually requires a sharp tap to display properly.
No one has mentioned office copiers. I love to smack them. It works sometimes.
Hookerbots that don’t know their place.
I used to have one of those
I’ve had various cheap PCs over the years, some of them with badly fitted innards. Occasionally they’d develop a buzz as something worked loose and began to vibrate loudly. A quick tap would cure it for a bit, until inevitably I’d need to open the damned thing up and repair it properly.
There was actually some logic to percussive maintenance for certain hard drives made back in the 90s. IIRC, one hard drive manufacturer reduced the number of magnets (or electromagnets) used in drive spin controller from something like 12 to 8. However, when the drive powered down, it would get stuck between two of the magnets so that it was just out of reach of the magnetic field and couldn’t get started spinning. Whacking it would move it enough so that it could start spinning up, and the electromagnets would take over.
My wife…
I’m surprised no one has mentioned computer keyboards. I’ve turned keyboards upside down and beaten the crap out of them a number of times.
I try not to smack the electronics about, but sometimes it is frustrating.
I have an old stereo receiver I bought off the scratch-and-dent rack back in the 80’s. It weighs around 12-15 pounds. I run my CD, DVD, cassette, phono and whatnot through it so we can watch football with full volume.
Sometimes, when I hit the power button, it doesn’t turn on. So I have to pick it up a few inches and let it drop back onto the shelf, shocking itself back into sense. It usually kicks on after the first drop. I like to think of the whole situation as enforcing my superiority over the machine. As in, “Do what I tell you to do or this can get a lot worse.”
Of course, once Skynet becomes sentient, it will probably start blasting music at me and try to drive me crazy a la Noriega style.
I have a tendency to resort to a short temper when electronics don’t work after having done everything my more evolved brain is capable of to fix it, so my characteristic quality of giving malfunctioning electronics a firm socking is not unusual. Still, it does have a great satisfaction to it when you’re so frustrated about the $1,000 you’ve defenestrated.
An older computer monitor of mine would often make terrible buzzing noises that were temporarily silenced with a menacing whack to the top of the monitor. I’m not sure about the mechanics to this, but, apparently, it’s common.
Uncle Brother Walker, I also own a stereo system that needs to be very strongly and loudly smacked (on the side) to turn on, so it has become customary to essentially make it fly across the living room whenever I must use it (and potentially scare guests who only wanted some background music).
I still have an iPod from when they had docks above the wheel and used hard drive(physical disk) memory. The disk gets stuck when I play particular songs and keeps turning, making intense clicking noises. Of course, the only way to make it stop is by hitting it against my palm repeatedly.
An interesting story about bashing television sets: my father tells me that in his time, any problem with it was resolved by a couple of persons grasping the television to the ground while someone gave it terrible, painful, and possibly passive-aggressive smacks to the top of it. Sounds a bit more caveman-era than anything, but it supposedly worked.
Imagine doing that to a plasma today…
Everything that has connections that can come loose/corrode/get dirty can potentially be fixed temporarily (or broken permanently) by percussive maintenance. There is one device that stands out in my memory, though, because rather than fixing or breaking it, smacking it made the problem mutate.
Back when double-sided circuit boards were a new thing in TVs, GE used little things they called “griplets” to connect traces from one side of the board to the other. They looked like pairs of star washers with a tube connecting them, and they were soldered to both sides of the board–poorly. As a result, they often came loose on one or both sides. Now, since they were scattered through every circuit in the set, this caused all manner of different problems; worse, when you smacked the set, it often jarred another griplet loose even as it fixed the first connection.
So, you’d see a set with no color. <SMACK>
Now it has color, but there are ripples rolling through the picture. <SMACK>
The ripples are gone, but the picture’s rolling vertically. <SMACK>
It stopped rolling, but the sound went out. <SMACK>
The sound is back, but it keeps changing channels on its own. <SMACK>
Fzz. Power supply shuts down.
When it stopped being entertaining, you’d open up the set and painstakingly solder both sides of every single griplet, and the set would work again. For a while.
This one has less to do with connection problems, and more to do with relocating the fan blade so it doesn’t bump up against something to make noise.
The fan in my computer has the same problem. One time, it even completely stopped until I hit it. I think it needs cleaned. Since it’s on top of the processor, I’d like to wait until I can get my hands on some thermal paste to bother. Until then, percussion maintenance seems to clear up any problems.
You’re married to a sexbot? 