LC475 -replaced 68LC40 for 68040 CPU

#1 Sat, 10 Jan 2009 - 18:30 68kMLA

I replaced the LC's 68LC40 with Quadra's 700 68040, but without the heat sink as it was in Quadra. Is this ok? or it will overheat? is the 68040 much hotter than 68LC40 version?

#2 Sat, 10 Jan 2009 - 20:12 68kMLA

You need a heatsink for the full 68040.

#3 Sun, 11 Jan 2009 - 03:40 68kMLA

You need a heatsink for the full 68040.

That's if you want to do it properly ;-) I ran a 475 web server for over 6 months with a full 040, no heatsink AND I disconnected the internal fan coz it was too loud. I eventually re-connected the fan but never bothered installing a heatsink. I then used that 475 for a further 2 years before I retired it to the garage (and set up a Q800 as a server instead) What I'm saying is that while a heatsink is recommended, it probably won't hurt you if you don't have one.

#4 Sun, 11 Jan 2009 - 11:34 68kMLA

Just have a look at the clock speed specifications of processor and motherboard. If the mobo is stock (25 MHz) it should do no harm to a MC68040 specified to run at at least 25 MHz (as any 040 sourced from a Mac will be), even without a heatsink. Like Flash! I use a 475 with full 040 but w/o heatsink; no problems within five years. If you have a heatsink at hand, consider to throw it in as it should improve the long term reliability of the system, however

#5 Sun, 11 Jan 2009 - 16:31 68kMLA

yeah i would agree if you got the heatsink use it. i have a similar setup and mine has a heatsink

#6 Sun, 11 Jan 2009 - 16:51 68kMLA

Mine has no heatsink and works fine. I would like to get one but I don't have any spares.

#7 Thu, 15 Jan 2009 - 01:08 68kMLA

If you can leave your finger on the CPU indefinitely, then it's definitely running fine. If you can't bear to touch it for more than a couple of seconds, you want a heatsink.

#8 Thu, 15 Jan 2009 - 07:00 68kMLA

If you can leave your finger on the CPU indefinitely, then it's definitely running fine. If you can't bear to touch it for more than a couple of seconds, you want a heatsink.

A good rule of thumb. :b&w:

#9 Sun, 18 Jan 2009 - 21:38 68kMLA

If you can leave your finger on the CPU indefinitely, then it's definitely running fine. If you can't bear to touch it for more than a couple of seconds, you want a heatsink.

Click to expand...

A good rule of thumb. :b&w:

Surely that should be 'Good rule of finger'!!

;D