How many different kinds of electronics can be fixed by smacking them?

[Autolycus]

And, for extra credit, how exactly does such a satisfying solution come about by such a visceral vicissitude?

So far I count TVs, VCRs, and car radios. Your turn.

[JKellyMap]

And, for extra credit, how exactly does such a satisfying solution come about by such a visceral vicissitude?

So far I count TVs, VCRs, and car radios. Your turn.

If you're the Fonz, any and all of them!

I'd add certain digital watches. And, I'd suggest maybe this belongs in MPSIMS.

[ColdPhoenix]

Jukeboxes.

Aaaaaayyyy *thumbs up*

[Colophon]

Jukeboxes, obviously.

And my DVD player, but that's not really an electronic fix, simply that the disc tray sometimes gets stuck and won't eject until I apply a level-2 percussive maintenance procedure to the top of the player.

[AClockworkMelon]

Space shuttles can be fixed by hitting them. That's how they do it in Mother Russia.

[Mangetout]

I've heard of people fixing (or rather, temporarily working around) computer hard drive problems on ancient machines by picking up a corner of the main case and dropping it a quarter inch. Not sure if that works on any recent hardware though.

[Colophon]

Wikipedia has an article (http://en.wikipedia.org/wiki/Percussive_maintenance) on this, including some "famous taps" from history.

The article mentions a few reasons why it might work for various applications. In electronics terms, I always assumed it was down to a badly soldered joint that can leave a gap in a circuit somewhere, which can be fixed by jolting it so that the conductors touch again.

[Tristan]

I have a digital 8 camcorder that occasionally gets messed up. After a year of thinking it was a pricey paperweight, some googling of the error code found me numerous instances of people saying the proper solution was to smack it, hard, in a specific spot.

Works like a charm.

Apparently some gear slips out of place in normal usage and....

[Machine Elf]

Wikipedia has an article (http://en.wikipedia.org/wiki/Percussive_maintenance) on this, including some "famous taps" from history.

The article mentions a few reasons why it might work for various applications. In electronics terms, I always assumed it was down to a badly soldered joint that can leave a gap in a circuit somewhere, which can be fixed by jolting it so that the conductors touch again.

That's pretty much it. Anything with a loose electrical connection or a stuck mechanism can be affected (in a good or bad way) by mechanical shock. OTOH, A malfunctioning solid-state device (e.g. a thumb drive with a flaky transistor somewhere inside) is not likely to be affected either way.

[Shot From Guns]

Ah yes, the wonders of percussive maintenance.

Personally, I do it for the cathartic effect more than out of any real expectation that it will fix something.

[cwthree]

Older-style desk phones (the big chunky ones) could sometimes be fixed by lifting the phone about 6 inches from the desk surface, then returning it to its original location with a solid, highly satisfying, thump.

[Jim's Son]

Also if there is dust or dirt preventing contact being made in a relay. I have to slap my machine at work a couple times a week to get the relay to work.

[ivan astikov]

My first Playstation sometimes needed a whack on the right side with a particularly sized screwdriver to get it performing again.

[statsman1982]

The fan in the desktop in my office sometimes gets noisy. A light tap on the side of the machine shuts it up nicely.

[Si Amigo]

The window switch in my car door sometimes needs a good wack to remind it whose the boss.

[needscoffee]

My old computer monitor.

[KneadToKnow]

My old computer monitor.

Confirmed. I have resolved problems with CRT monitors many times with percussive maintenance.

I now have an LCD TV/monitor that has an intermittent vertical line down the display which is fixable with a slight tap.

[Whack-a-Mole]

I was helping someone with a PC problem when another worker came by and said she had trouble with her machine. I walked over and her PC was powering itself on and off every few seconds.

I called our hardware guy and he came up, gave the PC a good thump and it powered on and stayed on.

Everyone was duly impressed.

[DCnDC]

I used to have a 1990 Volvo 240 whose O/D would disable itself randomly. The only way to remedy this was to whack the top of the dash.

[Todderbob]

The optical drive on my xbox 360 is going out. It refuses to read disks. 3 solid, swift whacks on top of the optical drive, timed properly while it's spinning up (about 3 seconds after the tray is flush with the system) work 80% of the time (the first time, and 80% the 2nd, etc), as such I see no need to spend 99 dollars sending it off to microshit getting it repaired.

[beowulff]

I have an expensive Fluke meter (http://www.mjs-electronics.se/images/Multi_dig/8840a.jpg) 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...

[dracoi]

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. :)

[Isamu]

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?)

[Doctor]

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.

[outlierrn]

Hyperdrive control panels

[FriarTed]

My old computer monitor.

Yep!

[Richard Pearse]

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?)
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.

[Dead Cat]

I own a pocket calculator that usually requires a sharp tap to display properly.

[campp]

No one has mentioned office copiers. I love to smack them. It works sometimes.

[EvilTOJ]

Hookerbots that don't know their place.

[outlierrn]

I own a pocket calculator that usually requires a sharp tap to display properly.

I used to have one of those

[Pushkin]

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.

[BobArrgh]

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.

[CC]

My wife...

[Canadjun]

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.

[Uncle Brother Walker]

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.

[Open Your Eyes]

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...

[Balance]

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.

[BigT]

The fan in the desktop in my office sometimes gets noisy. A light tap on the side of the machine shuts it up nicely.

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.

[Pushkin]

My wife...

You're married to a sexbot? :p

[Musicat]

My philosophy is...if it can't be fixed with a hammer...

Get a bigger hammer.

[Fridgemagnet]

And, for extra credit, how exactly does such a satisfying solution come about by such a visceral vicissitude?
The curious thing is, why does the problem not instantly reappear as soon as the violence stops? Often the "cure" will last a fair while. As others have pointed out, the problem is the connectors, invariably the weakest point in many electronic systems, and they don't get better as they get older. Now connectors (and switches and relay contacts etc) have a maximum current rating, which when exceeded will burn, melt or arc-weld the contacts. Less well known is that there is also a minimum current rating, below which the electrical connection can't be guaranteed. Generally, the higher the maximum current rating, the higher the minimum current rating too.

This minimum current rating is due to metal oxides, salts and sulphides, as well as thin layers of oil and general insulating dirt. This insulating crud can be punched through by a little voltage, and if this is followed up by the required minimum current the array of tiny sparks thus produced keep the insulating layer burned away. Bashing an electronic gizmo with an unreliable connection momentarily jiggles the contact mating faces such that the insulating layer is compromised, gets punched through by the applied voltage, and the connection maintained by the current. Switching the device off and leaving it for a bit may allow the oxides etc to reform, and the cycle of violence is satisfyingly repeated.

My first ever full-time job (some 20 years ago now) was as a TV repair technician in a Toshiba TV factory. Part of the production test involved someone hitting the top of the set with a big rubber hammer while it was powered up, and any that flickered or died were rejected to be repaired. We weren't issued with hammers, so I developed a technique of kicking the underside of the trolley the TV was sat on - very therapeutic, and it didn't mark the set. One time I performed this scientific manoeuver, making the TV jump a couple of inches in the air, only to turn round and see the horrified faces of a group of senior Japanese management who had come down for a visit. Bonus!

Anyhoo, the way around the dodgy connector problem is to use gold-flashed mating surfaces to resist the corrosion (expensive and still not totally guaranteed, plus gold plating is not good with high currents), or to use sealed relays and switches in a noble gas atmosphere (again, not good for high currents), or best of all, forgo the connector altogether and go for a well-crafted lead/tin solder joint, just like in the old days before labour got really expensive. I had an old '85 Mercedes for a little while, and the wiring loom was mostly solder-terminated. Very reliable. I've also got a weakness for big Citroens, which alas seem to be 20% shitty connectors by weight, and due to these I've had intermittent problems with airbags, headlights, climate control, tail lights, washer fluid low warning, fuel gauge, suspension control, and so on. Currently I'm occasionally being told that the radiator is about to boil over, which I'm ignoring as I know the engine is stone-cold, so I start it up in great clouds of white smoke (the fault throws the ECU), and then after a few seconds it self-clears and doesn't go wrong again for another day or two.

If you can isolate the offending connector by judicious jiggling, a squirt of proprietary switch cleaner aerosol and a few mating/unmating cycles will invariably cure the problem for a fair while.

And my DVD player, but that's not really an electronic fix, simply that the disc tray sometimes gets stuck and won't eject until I apply a level-2 percussive maintenance procedure to the top of the player.
Mine too. There's magnetic metal disc that drops down onto the centre of the DVD disc and clamps it to the motor platter. On my LiteOn piece of junk this magnet is now stronger than the mechanism that lifts the clamp on and off (either a weakening motor or a slipping clutch or belt, I can't be arsed to investigate further), and a sharp smack above the loader mech at the crucial moment is sufficient to encourage release/engagement.