| "Benderthe.evilrobot" <Benderthe.evilrobot@virginmedia.com>: Apr 08 08:17PM +0100 "pamela" <invalid@nospam.com> wrote in message news:XnsA7516B728743CD4AM2@81.171.92.183... > 20 seconds after the mains is disconnected. Also hard drives in > Playstations and PVRs will spin on. Telling impatient kids to go and > make a cup of coffee isn't going to work. You can't just lump everything into the same bracket - a lot of people just turn the TV off "cold turkey", its a lot better than leaving it unattended on standby. Anything with a hard drive can trash a file if you power down in the middle of a write operation. Some designs of SMPSU can go bang if you switch back on before the reservoir caps discharge and those with inrush surge limiting have a thermal recovery time for no protection - but it just stresses the components a little more than usual. Most user manuals seem more or less unanimous for about 30s. --- This email has been checked for viruses by AVG. http://www.avg.com |
| ohger1s@gmail.com: Apr 08 05:22PM -0700 On Saturday, April 8, 2017 at 3:16:40 PM UTC-4, Benderthe.evilrobot wrote: > --- > This email has been checked for viruses by AVG. > http://www.avg.com Most of this is dependent on the carefulness of the design. If power loss or brownouts is given consideration by the designer, none of this is a problem. |
| oldschool@tubes.com: Apr 08 07:33PM -0400 On Sat, 8 Apr 2017 20:17:20 +0100, "Benderthe.evilrobot" >time for no protection - but it just stresses the components a little more >than usual. Most user manuals seem more or less unanimous for about 30s. >--- I have a small low powered solid state stereo receiver. I noticed that things is always using power when it's turned off. A few weeks ago, while this receiver was OFF, I removed the speaker wires to test another amp. I then unplugged the receiver. Last week I put the speaker wires back on that receiver (it was still unplugged). There was a loud pop on each channel when I put the wires on it. (That was around 16 days later). Those caps must hold power for a real long time..... (There is no battery of any sort in this thing). Another thing, I have an external 56K modem that I use to connect (on dialup). Once and awhile if I shut off connection, later on, I have trouble connecting to the internet. I found that if I just shut the power off to that modem, it seems to reset it and thn it connects fine. BUT. I have to shut it off for about 30 seconds. Just ON-OFF dont work. I assume the caps need to discharge to do the reset.... |
| krw@notreal.com: Apr 08 10:05PM -0400 On Sat, 8 Apr 2017 20:17:20 +0100, "Benderthe.evilrobot" >You can't just lump everything into the same bracket - a lot of people just >turn the TV off "cold turkey", its a lot better than leaving it unattended >on standby. There is absolutly nothing wrong with "standby". >Anything with a hard drive can trash a file if you power down in the middle >of a write operation. Nonsense. There are many ways to design a device that will survive a power failure during disk write. A bit of reserve power is probably the best solution but a JFS works, too. >caps discharge and those with inrush surge limiting have a thermal recovery >time for no protection - but it just stresses the components a little more >than usual. Most user manuals seem more or less unanimous for about 30s. Only if it's designed by a moron. |
| alan_m <junk@admac.myzen.co.uk>: Apr 09 09:27AM +0100 On 08/04/2017 10:33, pamela wrote: > 20 seconds after the mains is disconnected. Also hard drives in > Playstations and PVRs will spin on. Telling impatient kids to go and > make a cup of coffee isn't going to work. Twenty years ago 5 seconds may have caused a problem due to the possibility of surges due to mains input filters. Often if the switch off is to cold boot crashed software then the internal PSU voltages have to decay. My rule of thumb is 30 seconds after any front panel LED has gone out. -- mailto: news {at} admac {dot] myzen {dot} co {dot} uk |
| David Woolley <david@ex.djwhome.demon.invalid>: Apr 09 09:35AM +0100 On 08/04/17 17:15, MJC wrote: > My Humax (old 9200T) will record even when in standby That's why I said you must make sure there are no recordings scheduled! |
| "Brian Gaff" <briang1@blueyonder.co.uk>: Apr 09 09:55AM +0100 In my view all devices should have a little pin hole switch that does this for you. It really depends on the device I think. Things like my Smart talk freeview box almost instantaneous resets are OK if done via the little plug from the psu on the back, but if you do it from the mains it needs a little longer as I suspect the wall wart has some capacitors in it. Phones are awhole other ball of nuts. Some seem to remember crashes indefinitely. there is one which is not out of production where the software crashes and stops the voice from working at all, even if you take the battery out. Sadly as nobody has the gear to reblow the software any more its a brick. Brian -- ----- - This newsgroup posting comes to you directly from... The Sofa of Brian Gaff... briang1@blueyonder.co.uk Blind user, so no pictures please! "pamela" <invalid@nospam.com> wrote in message news:XnsA7516B728743CD4AM2@81.171.92.183... |
| "Brian Gaff" <briang1@blueyonder.co.uk>: Apr 09 10:01AM +0100 Not many people understand computer shut down via the button either If software has locked up or is doing odd things, then a short tap on the power button, ie NOT the reset is normally the way to get a good shutdown. If that fails, then hold in the power button, NOT the reset button as this normally protects the hard drive from corruption. all these folks wo either press reset or worse, just pull the plug out deserve the reinstall they evenntually end up having to do. Brian Of course if there is a power cut this can happen anyway, and I've often thought of putting in an uninteruptable supply to allow proper shut down. they are not that expensive these days, and laptops of course have one built in. Brian -- ----- - This newsgroup posting comes to you directly from... The Sofa of Brian Gaff... briang1@blueyonder.co.uk Blind user, so no pictures please! "Davey" <davey@example.invalid> wrote in message news:ocadad$j1m$4@n102.xanadu-bbs.net... |
| "NY" <me@privacy.net>: Apr 09 12:21PM +0100 <krw@notreal.com> wrote in message news:sg5jeclipaol2ejgd0tuivrostvvad23bt@4ax.com... >>Anything with a hard drive can trash a file if you power down in the >>middle >>of a write operation. I suppose anything with disk-like storage (including flash drives) can be trashed if the power goes off during a write, though the time during which the files is in an inconsistent state between data sectors and sector map may be less with solid state than a mechanical rotating disk. > Nonsense. There are many ways to design a device that will survive a > power failure during disk write. A bit of reserve power is probably > the best solution but a JFS works, too. It depends what filesystem they use. NTFS is pretty robust but it requires a licence to be paid to the inventors which is why a lot of PVRs use/read only FAT/FAT32. If they are Linux-based they will be able to use filesystems which are more robust (I'm not very clued up on Linux). But I'd say that a design which trashes the file that is being written to or the whole filesystem when the power goes off (eg due to a power-cut, which is not totally unexpected) is a bad design: you need some form of resilience in terms of battery-backed supply until the file write is complete and consistent. I use my Windows 7 PC as a PVR (either Windows Media Centre or NextPVR) and I've occasionally had power cuts during recording. I've never yet lost the recording that was being made or the filesystem of the recording HDD (NTFS). OK, Windows may do a chkdsk repair after the PC reboots, but it seems to sort itself out. A UPS would be useful for graceful shutting down during power cuts, but it might be more trouble that it's worth. At present my BIOS is set to reboot the PC automatically after the power is restored. If the UPS keeps the power up and initiates a graceful shutdown, the PC may not boot back up once the power comes back. My wife bought a 3kVA UPS with her big Dell PC about 10 years ago. We didn't get round to setting up the UPS for a couple of years. By the time we did (and after the warranty had expired, inevitably) we found that it had virtually no battery capacity: the battery monitoring software (monitored by USB connection) showed the battery accepting charge and gradually charging up and eventually showing as fully charged, but as soon as the mains was removed, the battery discharged within about 10 seconds with a nominal 40 W lightbulb as the load. Utterly useless, and it wasn't even worth buying a replacement battery for it because the fault may have been in the charging circuit rather than the battery itself. APC didn't want to know when we asked what a repair might cost, so it went in the skip - a waste of money as it was never even used. Moral of the story: always try any new hardware during the warranty period! |
| Look165 <look165@numericable.fr>: Apr 09 02:17PM +0200 Generally, the off/on if too short implies caps (generally somme 100µF) not to discharge totally and if on again during this state, the result is unpredictable. Thje more the device uses power, the less this time is needed. Today, it seems that 10-15 s are enough. For a modem (ADSL or cable) it's OK. For a LCD or plasma TV too. To be secure, count on 20s. pamela a écrit : |
| krw@notreal.com: Apr 09 08:34AM -0400 >licence to be paid to the inventors which is why a lot of PVRs use/read only >FAT/FAT32. If they are Linux-based they will be able to use filesystems >which are more robust (I'm not very clued up on Linux). That's an economics decision. There is nothing cast in jello that says they have to cheap out, or even use an existing FS. JFS techniques are well known. Even if they do want to use a vulnerable FS, a proper power system design can guarantee a safe shut down. >is not totally unexpected) is a bad design: you need some form of resilience >in terms of battery-backed supply until the file write is complete and >consistent. Exactly so. This is common with flash-based systems. The power system has to guarantee at least the current block has been written. >recording that was being made or the filesystem of the recording HDD (NTFS). >OK, Windows may do a chkdsk repair after the PC reboots, but it seems to >sort itself out. NTFS? >circuit rather than the battery itself. APC didn't want to know when we >asked what a repair might cost, so it went in the skip - a waste of money as >it was never even used. Always test your emergency system. When I was in IBM, they tested the emergency generators once a month. I have no idea why they had such in the building I was in (just offices and a few labs at that time) but they were there, so the were tested. It's a really good idea to test your system backups from time to time, too. You may find the restore doesn't work. :-( >Moral of the story: always try any new hardware during the warranty period! Anything that's important has to be tested. |
| David Woolley <david@ex.djwhome.demon.invalid>: Apr 09 02:22PM +0100 On 09/04/17 10:01, Brian Gaff wrote: > If that > fails, then hold in the power button, NOT the reset button as this normally > protects the hard drive from corruption. As I understand it, a long press is handled by the hardware and forces a dirty shutdown. If it were handled by the firmware, it could be difficult to shut down a battery powered device which had locked up. RESET should be more gentle than a long press. Typically, power supplies will not have decayed before any sector write in progress has completed and disks should park. However, you are basically relying on fault recovery mechanisms to protect the physical media, and the low level formatting. Journalling file systems may protect the basic file structure, but data buffered in user space, and write back caches (OS and device) will not get written and very few application designers will have designed them to be completely safe against partially written files. Consumer devices have to be tolerant of such abuses, but whenever you start relying on fault recovery mechanisms, for normal operation, you are on dangerous ground. |
| "NY" <me@privacy.net>: Apr 09 03:14PM +0100 <krw@notreal.com> wrote in message news:g0akec5be84fpoh2a0dukvh2613de8i570@4ax.com... > emergency generators once a month. I have no idea why they had such > in the building I was in (just offices and a few labs at that time) > but they were there, so the were tested. The office building where I worked had huge diesel-powered generator to cope with power cuts. My office was near it, and I know it wasn't tested during office hours for five years. One day there was a power cut that affected the whole town, and the diesel engine fired up, amid a tremendous roar and lots of filthy black smoke. Power returned for about a minute and then there was a huge explosion and a jet of flames. Apparently the generator couldn't handle the load, even with the engine working as hard as it could (a good diesel grunt!) and something caught fire, igniting the diesel tank. Turned out that it had been specced back in the days when there wasn't a PC on every single person's desk, and it was woefully underpowered for the modern demands that were placed on it. |
| MJC <gravity@mjcoon.plus.com>: Apr 09 03:34PM +0100 In article <V-KdnUieLtZb3HfFnZ2dnUU78c_NnZ2d@brightview.co.uk>, me@privacy.net says... > The office building where I worked had huge diesel-powered generator to cope > out that it had been specced back in the days when there wasn't a PC on > every single person's desk, and it was woefully underpowered for the modern > demands that were placed on it. Conversely the possibly apocryphal story I heard had the generator tested regularly. When eventually needed it ran for a few minutes and then ran out of fuel. The protocol didn't include top-ups! Mike. |
| avagadro7@gmail.com: Apr 09 06:52AM -0700 http://www.nextstepus.org/news/wp-content/uploads/2014/04/Pre-1976-before-A.jpg |
| "fynnashba@yahoo.com" <fynnashba@yahoo.com>: Apr 08 01:39PM -0700 l am working on a Samsung refrigerator RB29H with a colleague. on switching the the machine the inside fan will start working in a few minutes but the condenser fan at the back and the compressor will never come on. however when l press the TEST switch on the main (computer/control) board, the condenser fan will start turning but the compressor will never start. Can anyone also tell the resistance of the temperature sensors at room temp? |
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