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Old 28 February 2012, 08:58   #2381
Join Date: Jun 2010
Location: out in the wild
Posts: 1,251
Originally Posted by Vlad View Post
I have the heat related issue with ACA 1231. My magic number is 55C CPU surface temperature, crashes start then. At 57C I have endless crash/reboot loop. 100 % repeatable.

1D1 mainboard, 3.0 kickstart, NTSC, A500 power supply, stock machine, only a laptop harddrive. Those temps are reached at idle. During the reboot cycle temp reaches 60C.
The temperature you're measuring is NOT the junction temperature, which is specified to be a lot higher for 68030 CPUs. The trouble with this small package is that junction temperature gets too high even with package temperature within limits (60 deg. C is not really hot). Like I wrote yesterday, a tiny heat-spread piece of metal makes sure that generated heat is moved away from the chip, making it 100% stable.

Originally Posted by Vlad View Post
Jens, couple of questions:

1. Is it possible to downclock the CPU at all?
Yes, it is, but it requires soldering, so you'll lose warranty. The easiest way is to exchange the crystal. CPU frequency is crystal frequency/2*3.333. Memory refresh period is independent of the crystal frequency, because it's generated from the A1200 frequency, so you're free to choose any frequency below 25MHz and won't violate RAM timings (there's even a little headroom for RAM timing - the calculated-but-never-verified max. number for the crystal frequency is 28.1MHz).

Originally Posted by Vlad View Post
2. Do you have official support forum?
I don't - I only give support via eMail. Contact me through my web form on for that. However, please note that the ACA1231 is an OEM product, so Vesalia is your first port of call for support.

Originally Posted by Vlad View Post
3. This heatsink kit from Vesalia:
a. Is there a timeframe for its delivery?
Later this week (shipping starts friday or saturday).
Originally Posted by Vlad View Post
b. There is a piece of tape with something that looks like serial number on the CPU, does it have any special meaning or can I just get rid of it?
It's your serial number, and you must leave it on for warranty reasons. It can also stay on when the heatsink is placed on top of it. The source of heat is the center of the chip, and that is not covered by the serial number.

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