CYRIX 386-486 Upgrade CPU and COMPAQ 386/20 HELP
David Longley
I have a Cyrix Upgrade Chip with heat sink attached to it. I'm
considering replacing the Intell 386-20 in a COMPAQ DESKPRO 386-20
(circa 1988).
Unfortnately, I can't see any orientation edge on the CYRIX Chip.
There's the CYRIX labelling on the underside of the CPU, but....
Is there sdome convention re the orientation of the labelling
on the underside of CPUs regardless of manufacturer? How can
one tell which way to insert the chip?
There *is* a white paint mark on the heatsink and I have indicated
its relative position by the 1 on the CYRIX chip relative to the
text on the underside.
Similarly, on the Intel chip, I have marked where the notch is
relative to the text on the underside.
Intel Underside Cyrix Underside
------------1 ------------
Ý 37434420AA Ý Ý1992CyrixUSAÝ
Ý MALAY 51 Ý Ý JAPAN Ý
Ý B Ý Ý Ý
Ý Ý Ý Ý
------------ ----------- 1
suspected
orientation pin
(white paint mark on heat sink)
Has anyone got one of these CPUs lying about without a heat sink on top
which gives some idea of the pin one location?
--
David Longley
Longley Consulting London, UK
Behaviour Assessment & Profiling Technology,
Research, Data Analysis and Training Services,
Small IT Systems http://www.longley.demon.co.uk
Kevin Kramer
The heat sink was attached by the cpu's prior owner, giving
little assurance of correct orientation. Closely examine the cpu for a
gold dot, a gold +, or a flattened corner as indicatation of pin 1. The
heatsink is attached by tape and can be removed with some effort.
Removing the heatshink should not be needed and is not recommended.
Reattaching the heatsink will cerainly provide lesser heat conductivity.
That tape does an amazingly good job of transfering heat. At 20mhz the
cpu shouldn't get too hot but it wouldn't be a good idea to test it with
your finger. Unless your hiding from the authorities and wish your finger
print removed. :-)
Kevin
David Longley (Da...@longley.demon.co.uk) wrote:
: I have a Cyrix Upgrade Chip with heat sink attached to it. I'm
David Longley
In article <6062jc$ee5$1...@earth.superlink.net>
bci...@saturn.superlink.net "Kevin Kramer" writes:
> The heat sink was attached by the cpu's prior owner, giving
> little assurance of correct orientation. Closely examine the cpu for a
> gold dot, a gold +, or a flattened corner as indicatation of pin 1. The
> heatsink is attached by tape and can be removed with some effort.
> Removing the heatshink should not be needed and is not recommended.
> Reattaching the heatsink will cerainly provide lesser heat conductivity.
> That tape does an amazingly good job of transfering heat. At 20mhz the
> cpu shouldn't get too hot but it wouldn't be a good idea to test it with
> your finger. Unless your hiding from the authorities and wish your finger
> print removed. :-)
>
>
> Kevin
>
Actually..... that's been very helpfull - one closer examination
THERE IS a small gold dot just at the corner of the central gold
square which is a the designated suspected pin 1 position below -
ie which corresponds with the paint mark on the heat sink.
Many thanks - it helps to know what to look for.......
--
David Longley (check end reply line #)