- Heat sink grease - 5 Updates
- On Trolls - 1 Update
- Rechargeable battery question - 2 Updates
| jurb6006@gmail.com: Apr 19 05:09PM -0700 >"In my opinion you should never 'squeeze' it tighter than the clip / fastener is going to hold it. Otherwise you squeeze too much out and are left with voids. " Disagree. What seem like voids are either the points of actual metal to metal contact or so close that you can't see the compound. Remember I said a bead or daub, if it is spread it is almost for sure not even and that will cause actual voids where it traps the air at the low spots of the compound. Some of those clips are too weak to overcome the viscosity of the compound, and some of that aluminum stuff they make the heatsinks out of is very soft and the screws might strip. The main thing is not to let it come up or move. If it is done right they are usually stuck pretty good though. >"I've done a lot of work on laptops, a lot of them nasty to get into so it's best to do it right first time." Agreed, with anything. It's been said "How come there is never enough time to do it right but always enough time to to it again". I have even told people now and then "Hell no I don't want to do it right, I just don't want to do it again". I also don't want the liability, if the part fails guess what ? >"I've also lapped more than my share of CPU 'spreaders' (IHSs) and (desktop machine) heatsink bases. " I haven't done that many processors in PCs, I just follow instructions. I did much work in power supplies and amps, unfortunately lapping is simply impossible on most. I also agree with Jeff Leiberman's caveat about making the surface concave. If you do that it could be worse than not lapping at all. I only lapped in some output ICs once actually. I was extremely low on compound so I thinned out what was leftover and lapped with it. The ICs required no insulator being a totally plastic package. At the end of the lapping I had them in position and moved no more so that if there were any larger particles in there they would stay put, embedded and not keep the surfaces away. The only reason I was even able was because I was retrofitting a pair of LM3886 in place of a big STK and made a clip that went from one mounting screw to the other. I had plenty of room. (I would have put i pre outs and had the guy use an external power amp but the damn tone controls were in the global feedback loop) Luckily I don't have to do much of that anymore or I would have a caulking gun full of compound like this one place I worked. Makes it easier to apply and I would never run out. They did but it took years even with a bunch of techs working. I've been hearing of laptops with mo fan, and of course smartphones don't have them. Will it eventually get to the point where they don't need heatsinks ? Get an efficient enough switch and it could happen. I have already seen power switching transistors with no heat sink except the tab itself. At 0 Vcesat, 0 Vceo, 0 Vbe, 0 tOFF and 0 tON there is no heat to sink. |
| Jeff Liebermann <jeffl@cruzio.com>: Apr 19 07:29PM -0700 >...I also agree with Jeff Leiberman's caveat Argh. It's Jeff Liebermann. Spell my name correctly or I shall call upon the gods for divine retaliation. Heed this first and last warning lest the wrath of the gods fall upon thy house, when darkness shall envelope thy LCD monitor, and a plague of bugs infest the software by which you have taken my name in vain. >I've been hearing of laptops with mo fan, and of course smartphones >don't have them. Most of my Chromebooks do not have a fan. Heat is conducted from the CPU to either a metal case or the metal shield on the bottom of the keyboard. >Will it eventually get to the point where they don't >need heatsinks ? Methinks not. For every decrease in CPU power consumption, there is an equal and opposite increase in clock speeds. The result is that the maximum power remains about the same or slightly lower. However, when the CPU is at idle and not active, the power consumption is much lower. >seen power switching transistors with no heat sink except the tab >itself. >At 0 Vcesat, 0 Vceo, 0 Vbe, 0 tOFF and 0 tON there is no heat to sink. There's also no signal. Might be an IGBT FET. Very low Vce(sat) at high currents. However, it's not zero, so there's still some heat that needs to removed. -- Jeff Liebermann jeffl@cruzio.com 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558 |
| jurb6006@gmail.com: Apr 19 10:09PM -0700 >"Argh. It's Jeff Liebermann. Spell my name correctly or I shall call upon the gods for divine retaliation. " So you're the pagan sorcerer responsible for my internet outage of a few hours today. >"Most of my Chromebooks do not have a fan. Heat is conducted from the CPU to either a metal case or the metal..." Something that is not plastic ? Isn't there some law against that ? >"For every decrease in CPU power consumption, there is an equal and opposite increase in clock speeds." I stopped all attempts at overclocking in the Pentium 2 days, but I grasp the concept. However, from what I have gleaned the processor speed is not the end of the world usually. In a PC for example the RAM is slower, the HD slower than that, and so on until we get to the speed of access to data sources, i.e. the internet. So conceivably couldn't they just not crank the clock to the max and save power and generate less heat ? Or do they already do that ? My laptops have a setting, performance, balanced and battery life. Is that possibly an indirect "underclocking" control ? If not, what is it ? >"Might be an IGBT FET. Very low Vce(sat) at high currents. However, it's not zero, so there's still some heat that needs to removed. " The current should not be that high, all that current is cumulative right ? Seems like the main issue is charging and discharging the input capacitance. As such,lower clock speeds should be quite effective. If they could get it down to the point where no heatsink is needed at all, wouldn't there be enough advantage in cost to justify a slightly lower clock speed ? A phone accessing the internet for example, how much does that clock speed really mean then ? I am not being sarcastic here, that is a valid question, (I think) how processor intensive is all this ? Maybe there is advertising value. I could see the yuppies in the cellphone store looking at specs and saying "LOOK, this one has a higher clock speed !". Or are these the issues that keep the engineers up at night ? |
| gregz <zekor@comcast.net>: Apr 20 07:37AM > If we made CPU's and heat sinks with the same precision as your gauge > blocks, then we wouldn't need thermal paste or even mounting hardware. > The two surfaces would stick together by themselves. I think the screw down components can warp under torqueing, but flat seems good to try and achieve. I noticed some power modules were not perfectly flat, and I started to sand them on a flat precision table. They were pretty far off from flat. Greg |
| tabbypurr@gmail.com: Apr 20 07:49AM -0700 > >"For every decrease in CPU power consumption, there is > an equal and opposite increase in clock speeds." > I stopped all attempts at overclocking in the Pentium 2 days, but I grasp the concept. However, from what I have gleaned the processor speed is not the end of the world usually. In a PC for example the RAM is slower, the HD slower than that, and so on until we get to the speed of access to data sources, i.e. the internet. OTOH the CPU does a lot more than the others. Sometimes cpu is the limiting factor, sometimes not. IMLE with clocking it did make a significant difference. I don't bother clocking now, but once it was a deal maker. > So conceivably couldn't they just not crank the clock to the max and save power and generate less heat ? Or do they already do that ? that's done nearly all the time. It's one reason why most CPUs are clockable. > My laptops have a setting, performance, balanced and battery life. Is that possibly an indirect "underclocking" control ? If not, what is it ? probably. It also affects HDD power down settings on HDD equipped laptops. > high currents. However, it's not zero, so there's still some heat > that needs to removed. " > The current should not be that high, all that current is cumulative right ? Seems like the main issue is charging and discharging the input capacitance. As such,lower clock speeds should be quite effective. There's capacitance everywhere that gets charged & discharged each time it changes between 0 & 1. There's also that conduction overlap time when something changes state. > If they could get it down to the point where no heatsink is needed at all, wouldn't there be enough advantage in cost to justify a slightly lower clock speed ? you need a huge speed reduction to go heatsinkless. > A phone accessing the internet for example, how much does that clock speed really mean then ? I am not being sarcastic here, that is a valid question, (I think) how processor intensive is all this ? Modern net browsers are real cpu hogs > Maybe there is advertising value. I could see the yuppies in the cellphone store looking at specs and saying "LOOK, this one has a higher clock speed !". > Or are these the issues that keep the engineers up at night ? As more & more gets squeezed into a cpu, power use per flop has to fall dramatically. There is no other way. The future lies with very low power gates relative to today. NT |
| jurb6006@gmail.com: Apr 19 10:16PM -0700 I'm doing much better I let Slowman pitch his manure in SED a couple of times now and did not respond. I am JURB and I am trollfeederaaholic. Step one : To recognize the problem. Step two : Yeah, we need TA like AA. The 12 step program to recovery. One day at a time. Easy does it. We can even use the same bumper stickers and avoid those "routine" traffic stops. |
| "Ron D." <ron.dozier@gmail.com>: Apr 19 12:23PM -0700 I've had no issues replacing Ni-Cds with Ni-mH for vTech cordless phones. A pack with 3 AA batteries in series. I have extra connectors and wire now. 5-7 year life. |
| mike <ham789@netzero.net>: Apr 19 05:05PM -0700 On 4/19/2018 9:15 AM, Jeff Liebermann wrote: > If you look at photos of commercial spot welder electrode tips: > <https://www.google.com/search?q=spot+welder+electrode+tips&tbm=isch> > methinks you'll find that most of them are copper, not brass. Perhaps that's what I meant by line two of the quoted part... "I wouldn't use it for anything high current tho..." Somebody nitpicked my use of the word, "weld" with brass. I'll rephrase... One can use an energy pulse directed through hobby store brass sheet cut into strips to effect a connection to a cell very easily, but the resistance is slightly higher precluding use in applications that require high current, and may pose corrosion issues in unfavorable environments, otherwise it is easy to do and works well for many applications for those who don't have sophisticated spot welders, a supply of the proper tab media or a desire to 'school' the poor fool who made the suggestion with links to basic principles and value a working battery higher than nitpicking the suggestion that someone use something imperfect in their eyes. Methinks thou dost protest too much. Brass is perfectly adequate for a metal detector. Stated another way...If I didn't have workable alternatives, there'd be no reason for me to post. Scientists like perfection. Engineers are happy when it gets the job done. |
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