Some electronics will rebel if used for too long a period of time. On long road trips my car’s CD player will putter out after about 2 ½ hours. My DVD player will start to freeze up after about 3 to 4 hours (it’s difficult to watch the Lord of the Rings Spec Eds).
These devices are not broken. They will work just fine after about an hour of rest. It is my uninformed layman’s understanding that they can’t work when they get too hot.
So why does this happen? is it really the “hot” thing? Is it less likely to happen in higher quality electronics?
If, prior to a movie marathon, I were to place an ice pack on top of my DVD player would that help the situation?
One reason it gets hot is because in the power supply it has to change the incoming volts to a usable amount of volts. well the volts that get kicked out are turned into heat. this is one reason why it gets hot. I added a fan to my dvd player and no Higher quality doesnt matter cuase mine is a sony 5 disk big old piece of papper weight. If your dvd player is in an entertainment center then your more likly to get hot than if it just sits on top of something.
as for the cd player in the car… You have heating vents under your dash and most likly one runs by your cd player. I bet you anything it would well if you had you air conditioner off.
Some things are purposely designed to only be operated for short periods, then rested. Some power tools I have are clearly specified as such, like a staple gun that specifies a maximum number of staples you should run through it in a five minute period.
But it shouldn’t happen to a CD player in a car.
Shouldn’t happen to a DVD player either. Have you got adequate clearance around the thing? Haven’t covered up the ventilation holes or anything like that?
I wouldn’t recommend the ice pack (ahh, nostalgia - a carton of frozen milk was what we used to cool our overheating Sinclair ZX80) - it might cause condensation which could lead to a short circuit or corrosion.
In the DVD player, it is probably just a key component that is overheating (some kind of graphics processor that handles the decompression perhaps?) - if you’re feeling brave and adventurous, and you don’t mind trashing the warranty, you could open the case and see if there’s any potential for installing a heatsink and fan (although finding something to power the fan might be a challenge).
My player runs hot, but it hasn’t yet caused a problem.
My old Hayes 1200 baud modem used to overheat. A cold glass of ice water made it run okay. You know: putting it atop. The modem couldn’t drink or anything, and even I knew then that it’d be a bad thing to pour the water in!
I almost panicked a few months ago when my TiVo overheated! I’d just re-arranged the entertainment center to replace the DVD player and finally toss the VCR. Turns out my receiver (which has great big transistors) was causing it. Luckily the TiVo didn’t die, and I put the receiver in a different location. This all in an enclosed entertainment-center-style cabinet.
I’ve always found it interesting that one of the items on a TiVo’s status screen is it’s internal temperature. Is this the only piece of consumer electronics that reports it’s internal temperature as a standard feature? (I know some people add temperature sensors to their computers but I don’t know of one that comes with that feature standard. And, I’m obviously ignoring ovens and the like here the function of which is to heat things to a certain temperature.)
Almost all newer mainboards and processors have built-in temperature sensors and can show the core temperature and case temperature in the CMOS settings. Software can read this too and show you the temp in Windows.
To elaborate: While transformers do generate some heat, unless the transformer is defective, it is generally a trivial amount. The transformer does the majority of the voltage reduction.
However, if a poor choice of transformer was made, or your house’s voltage is higher than usual, the voltage regulator will have to work overtime, getting rid of excess voltage. The voltage regulator can generate a lot of heat, depending on how closely the output of the transformer’s secondary matches the application’s requirement. I’m not really an expert on modern electronics, but I’d guess that anything that is computer-based (like a DVD player) would require a regulator.
Circulation. Good air circulation is your friend. There must be room to allow convective currents to form, pulling cool air in and letting hot air rise.
A lot of consumer electronics are desgined and tested for conditions assuming they are operating alone, sitting on a tabletop with freely circulating air on all sides. Tuck it in a tight bookshelf, or enclose it in a vehicle console, and you cut off air circulation, and components overheat.
So, see if there’s some way you can ventilate the console your equipment is in, and if necessary, add a fan to force circulation.
tanstaafl, like Q.E.D. mentions, a TiVo is merely just a computer. It’s a PowerPC motherboard running LinuxPPC, with a regular computer hard drive (mine sports a Maxtor presently, but came with a Quantum [who’s now Maxtor]).
Running with Scissors, most power supplies for the vast majority of consumer electronics (and industrial, in my experience) aren’t transformer-based (“linear”) power supplies any more. Transformers are heavy, more difficult to design, and use expensive materials, plus, as you say, are more dependent upon the input voltage. Then you need a voltage regulator in addition to this in order to get the 12 volts DC (or 5VDC, or whatever) that you device really uses and to keep it stable. No, what’s used more often these days is a “switching” power supply. They rectify (convert into DC) the line voltage to a known level, then run this through a transitor circuit (“the switch,” I guess; I’d call it an inverter myself) which gives an alternating DC current (pulsed DC you could say) which is then run through a rectifier again. The advantage is it’s all solid state. This means it’s light and inexpensive. It’s even not all that tricky to design. There’s not considerable heat generation. The inverter part of this type of supply is really the key to its success – by varying the DC frequency, it can maintain constant voltage output given a dynamically-changing load. Coming off a pure transformer, you’re likely to start dropping more voltage as you consume more amps.
So, I did say my receiver gets hot because of the transistors, so what’s the difference? Well, they’re for the amplifier part of the receiver, the power amplifier. The transistors are bigger and do their job a lot differently in this type of application.
bienville, also consider that your dvd & cd have mechanical (moving) parts as well as solid-state (electronic) parts. Not knowing the exact nature of your problem, the mechanical parts could be overheating and expanding outside specs, not allowing the dvd/cd discs to spin or read properly.
Although I’ve had solid-state parts overheat, they’re usually lunched for good. The mechanical parts cool down and if not permanently damaged, work again.
At work, I am encouraged to leave the solid-state devices on all the time, even on weekends & holidays as the pulse from turning the units on & off do the most damage to the circuitry. With things like hard drives (an electronic/mechanical devise) we turn them off only on weekends & holidays.
If you’re implying switching supplies are not “transformer-based,” then this statement is incorrect. Almost all switching power supplies use a transformer to achieve isolation. The advantage of a switching supply is that the transformer is much smaller and lighter when compared to its linear counterpart. This is because the switching frequency of a switching supply (typically in the kHz range) is much higher than the frequency of a linear supply (60 Hz). All else being equal, higher frequency = smaller and lighter transformer.
I would also disagree that switching power supplies are used in the “vast majority of consumer electronics.” While I believe there is certainly a trend in that direction, many appliances still use a linear supply.
Precisely. This is one of the main reasons that commercial aircraft generators put out 400 Hz AC. In fact this same principle allows the generators themselves to be smaller for a given output power capacity.
I went on a road trip (it was about 1500km) this spring, and I tell you, my car got ‘tired’! It was much more likely to stall during the trip than during the rest of the year when I don’t drive it much.
It didn’t get ‘tired’ at predictable times, like after driving 300km… it got ‘tired’ in the morning after driving 5 km.
Since that it’s rarely stalled. (‘rarely stalled’ in the way that you can say about a '92 Plymouth Acclaim with over 200,000km).
Crafter_Man, I didn’t mean “don’t use transformers.” I guess by “-based” I mean the primary thing that makes them work. I think I did mistake “vast majority of consumer elelectronics,” though, because I need to remember that just about every piece of less-expensive hardware I have still uses a transformer! The telephone, cable modem, router, scanner, just about everything! The printer has a switching supply, I’m sure, and the computer, too.
Q.E.D., there is a slow-but-building trend toward DC (which is really mid-frequency) resistance welding in the auto industry for this purpose. A smaller, lighter-weight transformer means you can use a robot that costs half the price (doesn’t need to lift as much).
Balthisar: I guess the problem here is one of terminology.
The terms “switching” and “linear” were originally employed to differentiate between regulators that used used switching, which is non-linear, and those that didn’t. Those early switching regulators were used in a dc->dc situation, e.g. 20 V unregulated dc from a transformer/rectifier -> 12 V regulated dc. Switching regulators are inherently more efficient that linear regulators: the voltage dropping elements are either fully on or off, rather than “partly” on or off. When fully on they have very low resistance and low power dissipation; when fully off they have very high resistance and low power dissipation.
Of course, if you can efficiently regulate 20 V dc down to 12 V dc, can you also efficiently regulate 120 V dc down to 12 V dc, and do away with the transformer altogether? Yes, you can. But doing that violates safety codes in lots of places: there’s no isolation between the high and low voltage sides.
So most modern switching supplies rectify the 120 V ac, switch the resultant dc at 20 kHz or so to get a 20 kHz square(ish) wave, feed that into a tiny transformer, then filter the ac components out of the resulting low voltage dc.
It should also be mentioned that linear supplies have traditionally had “better” isolation specs when compared to switching supplies. I think the situation has improved, as I have seen switching supplies that are approved for medical use. (They sport very low leakage currents.) But many engineers still do not trust the robustness of switching supplies when good isolation is a requirement (despite what the specs claim), and often opt for a linear supply if the design can accommodate one.