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Help troubleshooting NeXTDimension board

edcross

Experienced Member
Joined
Jul 15, 2015
Messages
86
Hi forum, last night I tried to fit my NeXT Cube with a NeXT Dimension board without success. Here's the story:

The board seems to be properly fitted in slot 2 and gets power (generates heat).
Booting up in rom monitor and watching the operating system output as it loads, I fail to see the board being detected.
Opening Preferences and clicking on the icon with the two monitors shows: Not applicable.
My NeXT Cube has 32 megabytes of memory and tried booting with two different hard drive, other has NeXTStep 3.0, the other 3.2.

At this point I'm unsure if there are drivers to be installed before the board can be detected, I couldn't find any manual or guide online.

Any help, tips, or guidance is very much appreciated. Thanks!
 

edcross

Experienced Member
Joined
Jul 15, 2015
Messages
86
One additional information, the led light on my ND board is off at all times. Is this an expected behavior?
 

edcross

Experienced Member
Joined
Jul 15, 2015
Messages
86
Update, after some further testing and loading a set of specific NeXTDimension tests onto my NeXT Turbo Cube. http://www.nextcomputers.org/NeXTfiles/Software/Diagnostic_Utilities/DimensionBoard/

I'm starting to suspect my problem is related to the NBIC (bus interface). For some reason my cpu board and NeXTDimension aren't able to see each other, each board contains one NBIC in charge of bus communications. If one of them were to be bad, cross board communication would not be possible.

Iif anybody here happens to know how to verify if a NBIC chip is working, I would appreciate the information. Thanks
 

RetroDan

Member
Joined
Dec 13, 2020
Messages
20
So, here's the deal. You need to find out if your Cube board has the NBIC (NeXTBus Interface Chip) installed. Most 68030 Cube boards didn't have it installed, but all 68040 Cube boards do. Without the NBIC (and you should see 'NBIC present' or something similar in verbose boot if it is), your mainboard can't communicate with the NextDimension card.
 

edcross

Experienced Member
Joined
Jul 15, 2015
Messages
86
Thanks Dan, my cube has a 040 with NBIC plus I have a spare cpu board to test, perhaps the Nextdimension NBIC is fried,/
 

RetroDan

Member
Joined
Dec 13, 2020
Messages
20
It's possible that the caps on the ND need replacing. I recommend organic polymer caps.
 

edcross

Experienced Member
Joined
Jul 15, 2015
Messages
86
This is now fixed, the NBIC custom chip was bad, managed to source a replacement chip from Rob Blessin.
878c6738-3e0d-4eee-bf67-1fb71082e31e.jpeg - nextdimension nbic chip replacement
 
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