Re: white paste

Lostgallifreyan <no-one@xxxxxxxxxxx> wrote in
news:Xns97AEE30026B83lostgallifreyangmail@xxxxxxxxxxxxx:

"I.F." <dai.ode@xxxxxxxxxxxx> wrote in
news:_5S2g.2240$Y6.1264@xxxxxxxxxxxxxxxxxxxx:


The only problems with putting too much on are the cost of the paste
and what squeezes out when you re tighten the heatsink is messy! In
the years when I made my living servicing PC monitors & PSU boxes,
about 4 or 5% of PSU blowups were due to insufficient heatsink
compound. In every case, replacing the blown components and using
sufficient paste provided a permanent repair.




I've made money from repairs too. I've seen the damage that happens
when a power amp got too much paste to allow proper compression and
conduction of heat. Fixed it too, with proper method. I said this
twice now, because I don't want this point to get lost. If thick film
was the way, there'd have been loads there already, and the Mysterieux
said there wasn't.

Maestro Mysterieux, I've often left the original there like you're
suggesting. Check that it's ucontaminated by even a single hair
though. And smear inwards like I said in that other post. This will
give it a bubble- free profile and also remove surface contaminants to
a large extent. But if it's got furry while you were working, replace
it for sure.


Small followup:
Failures due to too little goop usually happen on small surfaces.
Failures due to too much goop usually happen on big ones.

PA and guitar amps usually have bigger heatsinks than the surfaces involved
in the large transistors used in PSU's because they mount several devices
on one plate them mount that to an even bigger one, or to the chassis.

It's easy to squezze a little excess from small parts, but very hard to do
it from between two plates of metal.
.

Relevant Pages

  • Re: white paste
    ... and what squeezes out when you re tighten the heatsink is messy! ... the years when I made my living servicing PC monitors & PSU boxes, ... Failures due to too little goop usually happen on small surfaces. ... suggesting scraping it so thin it has no chance of filling any voids, ...
    (sci.electronics.components)
  • Re: Intels heat sink grease
    ... If using heatsink paste produces more than a degree C ... improvement over a dry fit, I'd be looking for a heatsink with a better ... If the surfaces are in good condition, then very little TIM ...
    (uk.comp.homebuilt)
  • Re: Recommend transistors for PA at UHF?
    ... I recommend using "brick" RF modules. ... They are so simple...just mount them on a heatsink, wire up a couple of voltages, feed them with the proper input RF level and take the output from the module and run it through a low pass filter to the antenna. ...
    (rec.radio.amateur.homebrew)
  • Re: Too many radios?
    ... I think I may be able to mount them with the CPU ... heatsink directly to the pills, but I would need to do some measuring to ... blowing air over the white cap. ...
    (rec.radio.cb)
  • Re: tips for welding small aluminum bosses?
    ... you're on the right track with heatsink. ... aluminum mass you have welded on the other side of that plate. ... through the bushing.. ...
    (sci.engr.joining.welding)