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NeXT Development Board
- Thread starter haplain
- Start date
genie_mac
Well-known member
Interesting! Looks like someone has wirewrapped a circuit out of what seem like discreet logic chips, there's even some LED's as indicators there. Doesn't look like it's connected to the main bus, just to some connector on the back panel. SCSI maybe (did the NEXT have a 25pin SCSI connector?).
Some more hi-res pictures of the chips might give us a better idea of what is does (or should I say did
).
Some more hi-res pictures of the chips might give us a better idea of what is does (or should I say did
).
mcdermd
Well-known member
There were a couple of dev board kits:
NeXTbus Development Kit
NBIC Prototyping Board
Here is a thread about the NeXTbus dev kit: http://www.nextcomputers.org/forums/viewtopic.php?t=5
NeXTbus Development Kit
NBIC Prototyping Board
Here is a thread about the NeXTbus dev kit: http://www.nextcomputers.org/forums/viewtopic.php?t=5
Charlieman
Well-known member
Should we not assume that the colour coding is important? Looking at the top view:
* There are a bunch of amber/yellow labeled 16 leg chips which might correspond with the amber/yellow chip pack (possibly resistors).
* The blue labels match up with a plausible SCSI port. If It has 25 pins, I presume it belongs with the first NeXT box.
* The red label matches a bunch of chip packs. And a reset switch?
On the underside view:
* There is another amber/yellow chip pack, possibly for SCSI termination.
* There are connectors going to the plausible serial ports for debugging.
* There is a tie up point for common connections at the top left corner.
---
So it is a funky RAM/SCSI "thing".
* There are a bunch of amber/yellow labeled 16 leg chips which might correspond with the amber/yellow chip pack (possibly resistors).
* The blue labels match up with a plausible SCSI port. If It has 25 pins, I presume it belongs with the first NeXT box.
* The red label matches a bunch of chip packs. And a reset switch?
On the underside view:
* There is another amber/yellow chip pack, possibly for SCSI termination.
* There are connectors going to the plausible serial ports for debugging.
* There is a tie up point for common connections at the top left corner.
---
So it is a funky RAM/SCSI "thing".
techknight
Well-known member
Man... memories. That was back in the time period where you could actually wirewrap digital circuits.
Cant do that these days unless your running slow speeds. With todays speeds, and processors like the ARM, etc.. the slew, ringing, and other noise will destroy the circuits ability to operate.
Cant do that these days unless your running slow speeds. With todays speeds, and processors like the ARM, etc.. the slew, ringing, and other noise will destroy the circuits ability to operate.
Ditto. I doubt it's a SCSI port or anything of the like, given that it's composed entirely of little 14/16 pin chips. A high-res picture of them (or list of part numbers) could clarify if they're memory chips or just a big pile of TTL goo. What's most interesting is the fact that the PCB is missing the Nubus transceiver chips and there's no wiring running to the bus connector. The possibility exists that whatever circuit is implemented on that board hasn't anything to do with a NeXT workstation and someone was just using the card as a piece of perfboard to prototype something unrelated.Some more hi-res pictures of the chips might give us a better idea of what is does (or should I say did
(Or, the in-between possibility, whatever's on there is designed to modify the output of one of a NeXT's standard ports and connects to them via external jumpers, only using the card cage connector to provide power for the circuit.)
haplain
Well-known member
311 or something like that. Wasn't thrilled about that price but also didn't think that it was unreasonable for something that I've never seen and doesn't seem like there were many made. Heck someone probably has 300 bucks invested in their time wiring it up just as it sits. I'm going to go with that for piece of mind :beige:
Well, the chips on that board add up to it doing *something* interesting, but whatever it was it didn't interface directly with the NeXT's bus. (The wiring makes that obvious.) There's a handful of 4 bit binary counters, a few shift registers, and, most interesting, a couple of RS-422-compliant line drivers. If I had to take a wild guess it's some sort of serial data buffer or baud rate converter?
