Thanks for all the help! I will start some experiments and post the results.
Sorry for the "indescipherable string" I screwed up trying to reply with a "mailto:"; using the gmail-webinterface... Cheers, Jan 2013/7/14 Mike Isely <[email protected]> > > (see below) > > On Fri, 12 Jul 2013, Gary Buhrmaster wrote: > > > On Fri, Jul 12, 2013 at 8:24 PM, Jan Brouwer <[email protected]> wrote: > > ... > > > My unit does get pretty hot... I didn't think of cooling it before, so > > > maybe that would do the trick! > > > > Certain Hauppauge devices have a history of getting hot > > and resetting. Certain Hauppauge devices also have a > > history of having power supplies going (partially) bad > > (especially if they are a few years old). Either can cause > > "random crashes". Since it is (usually) the easiest to > > test (unless your computer is next to the refrigerator :-), > > I always swap out the power supply first. > > > > Yes, this is definitely the case. In fact, back in prehistory when I > was much more a hardware hacker than a software guy I learned that when > digital circuits misbehave the FIRST thing one should always suspect is > the power supply! > > To summarize various previous discussions on this topic, the things I've > seen over the years: > > These units do dissipate heat. If you have it sitting in the open > ambient air (with the room at a normal comfortable temperature) then it > generally should not be a problem. But if the device is in a closed-up > box where there's no air circulation or if perhaps it's stacked with > other heat-generating devices, then you may have problems with crashes / > resets. I do remember one specific tale a number of years back where > the user had stacked 3-4 24xxx devices on top of each other and then > stuffed them in a closed box. That didn't work out so well :-) > > I find that people get frequently fooled by bad power. The issue here > is that normal PC power supplies are in fact very forgiving of bad mains > - typical PC PSUs have large capacitors and a lot of internal > protection. They're designed to process/condition 300-700 watts without > wasting a lot of energy and it takes a good design to do that. I've had > PCs actually keep going perfectly even when the building power fails for > a fraction of a second. The monitor might wink out for a moment but the > PC just keeps truckin' along. > > USB-powered devices (well, those not connected to a powered hub...) have > the benefit of drawing power from that nice stable PSU. But any > peripheral which is self-powered with, say, it's own little power brick > is at a disadvantage. Power spikes, brown-outs, or just plain saggy > power won't affect the PC but the cheap wall-wart just can't defend > against crap like that. It doesn't have the same quality of filtering, > and it is just too small to have enough hold-up capacitance to survive a > dropout. That leads to situations where strangely enough pvrusb2 > devices seem to randomly crash while the PC itself is unscathed. > People frequently conclude that the device is flakey when in fact it's > just bad power that can't be compensated by a simplistic power brick. > > So people seeing pvrusb2 resets don't immediately suspect bad power > because, well, the PC is not crashing... > > Even a surge protector won't help the situation if the problem is > dropouts or sags - surge protectors just block damaging spikes and > filter EMI but they don't store energy to cover glitchy power losses, > even for a fraction of a second. For that you need a UPS, and one that > is fast enough on switchover to keep from glitching the power brick (I > think most modern UPSes meet that requirement). > > One big tip-off of bad power is if you can correlate pvrusb2 crashes > with external electrical events, like say your refrigerator cycling or a > nearby A/C compressor turning on/off. A sump pump could even glitch > things. Anything that can suddenly draw (or cease drawing) large loads > can do this. And inductive loads - like a motor - can really screw with > your power. > > And yes, I've seen reports of people who have correlated pvrusb2 crashes > with their A/C compressor cycling on/off. (Though it has been a few > years...) > > You won't be able to analyze bad power with a voltmeter (analog, DMM, > DVM, whatever..). The events you are looking for will be too fast and > the meter is usually filtered internally for slower (more readable) > response. If you really want to look for glitches, use an oscilloscope > - but BE CAREFUL - you're messing with high voltage + high current which > can seriously injure or kill you. You can blow up the scope if you get > the grounding wrong! Actually it would be safer instead to 'scope it > indirectly - say look at the output of a doorbell transformer wired to > the mains. Then at least it's isolated, current-limited 24VAC instead > of 120VAC or 240VAC (depending obviously on your country's power grid). > > Anyway, if you suspect bad power, one easy test for this is just to plug > the pvrusb2 device's power brick into a UPS. If you suspect heat > issues, try just using a simple desk fan to blow air across the top for > a while. If either experiment changes the behavior then you know you're > onto something. > > -Mike > > > -- > > Mike Isely > isely @ isely (dot) net > PGP: 03 54 43 4D 75 E5 CC 92 71 16 01 E2 B5 F5 C1 E8 > _______________________________________________ > pvrusb2 mailing list > [email protected] > http://www.isely.net/cgi-bin/mailman/listinfo/pvrusb2 > -- Jan _______________________________________________ pvrusb2 mailing list [email protected] http://www.isely.net/cgi-bin/mailman/listinfo/pvrusb2
