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Here's a poser for the assembled FTM intelligentsia ...

Recently I purchased an otherwise excellently performing Panasonic DVD recorder Model No. DMR-EZ48V, but I have noticed that:
— The right rear of the cabinet (above the power cord) becomes (very) warm, even when the unit is turned off.
— The cooling fan turns on every 20 minutes for 5 minutes when the unit is turned off; thus, even if the unit isn't being used, the cooling fan is on for 15 minutes every hour or for 6 hours a day.
As noted, this occurs when the unit is off (ie, in standby mode), with only the front LED display lit (dim), which is supposedly the only item drawing current under those conditions.

Nowhere is the operation of the cooling fan referred to in the 100-page manual of operating instructions (except to identify its location), including in the unit's specifications. Nor is there any mention of (over)heating in standby mode.

I have discussed this issue on several occasions with the selling dealer and with Panasonic customer service (both in Canada and in the USA) — to no avail.

I have been variously informed that:
— The cooling fan should come on when the unit is off only if Quick Start is on (which it isn't) or if ventilation is compromised (which it isn't).
— It's normal for the fan to turn on occasionally.
(The term "occasionally" would not seem to be justifiable or accurate when the problem occurs like clockwork 3 times every hour, 24 hours a day, 7 days a week.)
— This is not a ''known problem''; we've never heard of it before.
(It's known to me as a problem, for better or for worse.)
— Cable companies' PVRs have fans which run virtually all the time.
(I have no knowledge of this being either true or false. It sounds like a facile attempt at mitigation, although I don't know how that should apply to my circumstance.)


I even tried another unit (with the dealer's cooperation), and the exact same problem presented itself.

Beyond the apparent defect, the fact that the fan turns on and off repeatedly when the unit is not in use would indicate that the unit could constitute a fire hazard and could fail (ie, mechanical fan could wear out) in relatively short order.

Clearly, this issue is very disconcerting and frustrating.

So, if anyone out there has any intelligence to offer on the subject, I'd appreciate your sharing it with me.

While I'm not going to say anything firm about hardware/software that don't power down intelligently when not in use, the above I can comment on.

It's perfectly normal and in fact preferred operation in most cases for fans to come on in response to a temperature sensor hitting a threshold and running the fan until the temperature is brought down a few degrees. All macs have run (via PMU/SMC) for many years now, with zoned cooling and independently operating fans. Macs take a more advanced approach, with all fans running continuously but at varying speeds, with built-in tachometers for the SMC to monitor for fan failure. (in the case of a single fan failure, ALL fans, and there can be as many as nine, race at max RPMs for safety sake)

In less intelligent hardware, the fan merely clicks on/off as needed, either not running or running at max speed, which is the case for your unit. There are arguments for heating/cooling cycling of electronics, but in most cases with proper temp sensors, the fans actually do a good job of maintaining temperature around a fixed point, and the hardware rarely experiences dramatic temperature variations except when turning on or shutting off. The units that waste energy by keeping power supplies on when in standby, such as yours, actually deal with even less temperature variation, which prolongs the life of your hardware.

So in short, don't worry about it. While the hardware may or may not be operating as designed, there's no danger being presented, certainly no fire hazard. It may be wasting a dime or two a week more in electricity than it should is all, assuming it's supposed to be properly placing the power supply in standby or some low power mode. But some hardware simply isn't designed to do that, and at least some of the hardware has to remain fully awake to serve functions. A DVR box for example would have to mind the clock, check for scheduled recordings, download new schedules as they are provided or on a scheduled delivery basis, be available for remote query from work if you want to schedule something remotely, etc.

PS - if you're worried about the fan wearing out, most fans nowadays are brushless, liquid bearing, and by themselves have a ridiculously long lifespan. What wears them out is dust exposure. Certainly the more they run the more dust they encounter, but really your environment plays a much larger role. Something as simple as taping a bit of kleenex over the air intake on the unit could double the fan's life if you're really interested. Fan failures are a major cause of external hard drive enclosure failures. (lacie bigdisks... have seen sooo many die that way, but I suspect they were using cheap mechanical bearing fans)

Now that's an explanation! ... for which muchísimas gracias. You have allayed my concerns, and now I can continue to enjoy my máquina without worry.

A couple of footnotes:
— When the fan first starts up (as described), it seems to be at max revs, but after 2 seconds it drops down to a more leisurely pace, which is also fairly quiet and generally masked by other parts of the room's soundscape.
— The fan is indeed brushless. Thanks for the dust tip.

Follow-up:
Panasonic now advises that the DVD recorder is "working to specs" when it behaves in the manner described in my plaint.
The fact that nowhere is this information publicly available leads me to suspect that Panasonic (Matsushita) believes that it would discourage potential customers from making a purchase, if such were to be described in the company's promotional literature or in the recorder's operating instructions.
From my perspective, however, just knowing that it's normal and safe is sufficient — because it's a great piece of electronic gear.

Honestly, to me, it sounds like poor power supply design.

I would suspect, based on what you describe, that it uses a cheap "dumb" linear power supply, not an intelligent power supply. Linear power supplies consume power all the time when they're plugged in, and additionally regulate power by throwing off excess in the form of heat.

In this day and age, designing electronics that way is incredibly stupid. It's not just that it's an inefficient power supply; it's that the combined impact of such devices is huge. If Panasonic sells millions of devices that use that power supply, the overall impact in terms of power wasted when those devices are off is kind of astonishing.

On the other hand, I bet their marketing and instructional materials don't mention it simply because the engineers never thought to tell the technical writers about it. The technical writers who wrote those materials almost certainly don't have direct access to all the tech specs, and might not even work for Panasonic at all.

FWIW ...
According to the tech specs, the power consumption (when "on") is 40 w; in standby mode (ie, "off"), 3.5 w; with the Quick Start function enabled (also in "off"), 17.6 w.
My previous Panasonic VCR (1997) used 23 w when "on" and 7 w when "off"; and an even older one (1985) used 20 w when "on" and 7 w when "off".
So, by those numbers, the VCR/DVD recorder is using less power when "off" than the older ones.
By comparison, a Panasonic LCD HDTV (much like any TV these days) would consume (when "on") 55 w and in standby mode ("off"), 0.3 w — considerably less than CRT TVs with so-called "Instant On" in days gone by.

And, if one believes the numbers, then the added cost of the cooling fan's running might be (let's say) 7 w for 6 hours per day yields 42 w (0.042 kwh) per day, which at 12¢ per kwh comes to ca one-half cent per day or 3.5¢ per week or $1.84 per year.
Meh.

Well, that's the problem.

I just looked up Panasonic's financial reports online. For 2009, the last year I could find, they reported sales of 109,000,000 DVD recorders worldwide. By your figures, that's 4,578 kWh of power per day, or 1,670,970 kWh per year, just to run DVD players that are turned off. One and a half million kWh of power, for devices that aren't being used!

Multiply the number of DVD recorders sold each year by $1.84 per year and you're looking at $200,560,000 worth of electricity per year (at US rates), for DVD recorders that are turned off. Now multiply THAT by all the other devices Panasonic makes--DVD players, TV sets, DVRs, and so forth--that also consume power when they're off, and I think it's reasonable to say that their engineering choices have a very real cost.

Cool! (If that's the right word ...)

But let's not blame just Matsushita and forget the hundreds of millions of other electronic devices by other manufacturers out there which might guzzle even more energy ...
Methinks we have discovered the true source of global climate change ...

(As usual, a forum thread which has sped up to fly off on a tangent, escaping the surly bonds of earth to touch the face of God ...)

There certainly are a lot of folks out there other than Panasonic who make poor engineering choices with real-world implications, no doubt about it.

If I were to become King of the World, one of the things I'd do is to impose penalties on manufacturers who designed inefficient power supplies that consumed power like this when their devices were turned off. We read all the time about how an unregulated market increases efficiency and how government regulation imposes unrealistic burdens on the market that decreases efficiency, but the fact is that that's only true when the market itself accounts for its own costs.

When a business does something like dumping mercury in the local pond rather than paying to treat its waste, what it does is it lowers its costs of doing business by forcing the public to pay those costs instead. It's kind of an inside-out, reverse form of socialism--rather than the public gaining the profits from enterprise, which is what we normally think of when we hear the word "socialism," the private business gets the profit but the public pays the manufacturing costs.

When a business artificially inflates its profits by shifting some of its costs onto the public, other businesses can't compete on a level playing field. They have to either accept that if they pay the cost of treating their waste, they will not be cost-competitive with a competitor who is dodging that cost, or they have to start dumping their waste into the pond in order to be able to match their competitor.

I see devices with inefficient power supplies as something similar. They are cheaper to build than devices with efficient power supplies, but some of the secondary costs--namely, the hundreds of millions of dollars' worth of electricity, the extra power generators (and pollution they cause), and the costs of transmitting that power gets shifted onto the public at large. The businesses artificially lower their costs by forcing the entire public to pay those costs. It's upside-down socialism, and I think the evidence shows it's something that an unregulated market can not solve on its own.

I'm with you ... but I'm still keeping the recorder.