First a little background...

I've got four SuperCPUs, two of them are V1 64 units and two of them are V2 128 units. This story doesn't pertain to one of the 64 units since that particular SCPU was SCPU #1 (yes the very first one) and it can't use a ramcard, and I'm not about to send it in to get updated! Anyway, the other 64 unit and one of the 128 units has been very reliable for me.

The reliable 128 unit happens to be the first 128 production unit and it has worked great.

The troublesome 128 unit is about a 1 1/2 years old and it will lock up or crash on me periodically. But the problems   only happen when I run The Wave or my new Concept+ software. Both of these applications require SuperRAM and they set the processor into its native mode and operate within the SuperRAM (some of the time).

Anyway, the troublesome 128 unit is normally plugged into a 128 at home while the 64 unit is at work. A couple of weeks ago, something happened to the 64 unit and it quit working. So, I need to send that in to CMD to get it fixed. In the meantime, I brought the 128 unit to work and plugged it into the 64 to use. Everything is fine until I use The Wave or Concept+. So, I did some testing... I tried 3 different 64's and a 128. I tried different power supplies and even adjusted the voltage up on one of them. Nothing fixed the problem. I even swapped SIMMs around. No fix.

Then I decided to try the software with the RamLink disabled. How about that... no crashing. Enable the RamLink and the problems come back. In the RamLink at work as well as the one at home where this SCPU128 was being used, I have a 1750 plugged in with a large enough DACC partition created first in order to fill the 1750. This DACC partition is what I use for the Wheels OS to use as its ram.

 I rebooted Wheels while holding down the CMDR/LEFT-SHIFT key combination and installed the SuperRAM for the OS to use. I then tried out Concept+ again and it didn't crash on me even with the RamLink enabled.

I then exited to BASIC and created a second DACC partition in the RamLink. This DACC partition is the last
partition so it ends up residing within the RamLink ram instead of the 1750 ram. I rebooted Wheels again and installed this new DACC as the system ram. And Concept+ still doesn't crash.
So, my thinking is that this particular SCPU128 doesn't want to work very well if all of the following are true:

   * RamLink enabled with 1750 in rear port.
   * DACC partition for Wheels use is the first partition.
   * SuperRAM software such as The Wave is being used.

This has nothing to do with my earlier findings on the NMI interrupt problem that exists with the SCPU. That problem occurs no matter what the setup is. Concept+ doesn't use NMI interrupts, but The Wave does. But, I've fixed that problem in the software.
There can still be overheating problems with these units. Software can't fix that. The only cure is to get them to run cooler, like adding a fan or removing the back cover to get more air to the boards.

Anyway, if anyone using The Wave is experiencing frequent crashes and you happen to have a 1750 plugged into your RamLink and using a DACC partition as the first partition, try setting up another partition and using it. Maybe your problem will go away. I know mine did.

-Maurice