24 Feb
2014
24 Feb
'14
4:41 p.m.
On 02/24/2014 05:09 PM, Tony Duell wrote:
>> I noticed the video chip was covered with a
white gunk in a couple of the
>> units I opened in order to reconstitute my working one. I understand this
>> is some kind of substance which aids with cooling so that chip at least
>> runs very hot.
> White gunk will hurt cooling, not help (white interferes with
> radiational cooling).
>
> I take it you?re assuming it is silicone thermal grease. That?s
> plausible. But silicone grease only helps cooling if you stick it (in a
> *thin* layer) between the device and a suitable heat sink. The heat
> sink actually does the cooling.
Having several its white silicone based grease
to transfer heat from the
chips
to the the surrounding shield, which is there for EMI/RFI prevention.
Allison
I seem to remember in the TI99/4A that I had apart
there is a metal
screen (shield) around the PCB. A couple of the ICs (I forget which ones)
had silicone grease on them which effectively allowed them to use this
screen as a heatsink. I am not sure it was a very good heatsink, but..
-tony