On 10/12/2018 10:19 AM, John-Del wrote:
On Friday, October 12, 2018 at 8:36:35 AM UTC-4,
wrote:
"The grease has dried out..."

I guess now would be a good time to dispel this old husband's tale.


When the union between heatsink and transistor is undisturbed,
dried out grease that is like cement is perfectly fine.

You beat me to it. It's not the liquid component of heat sink
compound that transfer heat, it's the solids that are suspended in
the goop. The compound may get hard, but the solids are still packed
between gaps doing their job.

Provided they're really undisturbed. Thermal cycling can cause
delamination problems that don't occur with the oil present.

Cheers

Phil Hobbs

--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC / Hobbs ElectroOptics
Optics, Electro-optics, Photonics, Analog Electronics
Briarcliff Manor NY 10510

http://electrooptical.net
https://hobbs-eo.com