Alpha error memory intergrity check failure

[rwalker192]

I have a bally alpha I just got that had no feed to the screen. It is a Butterfly bonanza.  It had the 501-021 board in it. I swapped it with a pca39456 board and the screen came to life. I did a clear and it started to boot, then close to the end it stops and I get this error: Machine Fault. memory integrity check failure for user process at addr: 710832128 flags 80010068 digest. I swapped the software card with a different game and it loaded correctly.

So my question is do I have a bad software card or an I missing something?

Thanks
Bob

[rickhunter]

There are different 39456, there's a -0 and there's a -4, big difference.  The -4 is a 1Ghz/1GB RAM mpu, the other one is a 400Mhz/512MB RAM.  I believe the Butterfly Bonanza requires the 1Ghz CPU with 1GB of Ram, the 39456-4 type, or the newer expandable 204934-0 (these are the ones with the removable 1GB Simms and can accomodate 2 simms for a total of 2GB).

[rwalker192]

Thanks Rick
That explains the problem I'm having. The board that was in it had the removable sim card in it.
I'll order a 4 tomorrow.

[rwalker192]

As a follow up question: when it starts with the original board the monitor will go vga in then no signal, Is there is something I can look for to fix this or just replace the board?

[rickhunter]

Does the mpu have a vertically mounted VGA card in it for video?  Or does the monitor plug into the video port on the mpu?  I would also check the power supply in the mpu to make sure it works.  The removable 1GB simm can also cause issues.

[rwalker192]

Thanks Rick you were correct. (as always) The 24v power supply was bad.