Turbo Motherboard not recognizing ND

Started by gtnicol, October 17, 2011, 10:21:51 AM

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gtnicol

This is the first time I've ever seen this issue.

I have a ND that other motherboards recognize and work fine with, but with a particular turbo motherboard, the ND isn't recognized. The motherboard has V74 ROMs and appears to have an NBIC chip as well (there is something covering the NBIC area, though it looks thinner than other NBIC chips).

Any thoughts?

gtnicol

I had another look at this board and during booting, the NBIC isn't recognized. Does anyone have experience debugging NBIC issues? I would imagine the chip itself should be fine?

barcher174

Ouch. That's going to be tough. The nbic doesn't have much of a footprint as I recall except a direct connection to one of the ASICs so I would expect it could actually be the chip itself.

gtnicol

That's not an easy chip to replace either. I do have some spares.

Rob Blessin Black Hole

Hello Gavin:  Some of the NBIC's are socketed but a light bulb went off for me here as I have a NeXT Dimension Board we just recapped , it lights up the screen but is not recognised at boot   I'm going to try a different 68040 board and make sure it recognises the nbic chip as well ... no joy with the second board , with no ram it doesn't light it up , I tried different ram and it lights it up but is not handshaking , it does have new caps and Matt my cap guy noted that one of the  caps  had previously pulled pad .  His repair new cap looks good  but not sure if that is te issue, Brian I'll send it along with those Color motherboards and see if it is something  that is reapirable, the system was used at TRW :)
Rob Blessin President computerpowwow ebay  [email protected] http://www.blackholeinc.com
303-741-9998 Serving the NeXT Community  since 2/9/93

Rob Blessin Black Hole

Hello NeXT Community: I figured this one out when I added a second dimension board it scrambled the mono signal so I took a very close look at the board and found what I think was a capacitor clipped wire or paper clip that was stuck in the pins on the back side of the dimension board by the connector bridging the wires.
In fact it looks like it was a factory mod then I thought that does not make any sense, and there was no solder , it was like at some point someone involuntarily sabotaged the board which probably sent it into retirement, the Cube was From TRW. Removing the wire solved the problem and with new caps she runs perfectly. I have seen this issue before so now I know a further check of the Dimension connector where it mates with the cube backplain may resolve it as it is probably not a one off case :) It may help someone diagnose a flaky board as it is the last thing you would think of the board lights up and NeXT probably had a fail safe check to prevent it from booting on the dimension board side if it encountered a short fortunately it did not cross the wrong set of pins which may have resulted in blue smoke..   The wire was the same gage as the dimension board connector pins so it may have been there all along from the factory at any rate problem solved 
Rob Blessin President computerpowwow ebay  [email protected] http://www.blackholeinc.com
303-741-9998 Serving the NeXT Community  since 2/9/93