Hi there. My name's Dave. I'm a PCB designer from Austin, TX. I emigrated to the US from the Uk in 1998. I worked their mainly on the original black box 68K machine - the Sinclair QL. I used a NeXT box as part of my career. It was used to do visualizations of complex data that was being crunched by a Cray XMP. Those were the days.
I have a Cube and a slab, both mono and both complete with keyboards and monitors. One of the monitors has issues, but the other is fine.
I plan to develop some hardware for my machines that I will also make generally available. All my projects will be open hardware under a permissive license.
The two projects I am currently working on are a modern PSU replacement for Cubes and a 10/100(/1000?) Ethernet card also for Cubes. The included 10 mbit ethernet is slower than a slug in an icecube, and on the '030-based machines it's AUI, which is a frustration too.
I'm looking forward to making a few posts and having some educational discussions. Right now I can't fully follow a lot of threads as I can't view attachments, but with a few posts I hope that ability will be unlocked. I've been on the FB group for a good while, but only just developed the need to register here because everyone there kept talking about links to here ;)
Thanks for having me.
Dave
Welcome to the forums Dave!
Indeed, welcome! And, yes, lots and lots of info available hereabouts.
And given the early start to the "big heat" in Austin this year (I lived in Round Rock from 1993-2000, working for Cypress Semi), you'll want to spend lots of time indoors this summer with your NeXT boxes.
Granted that I don't need to shuttle around much data to/from my NeXTs on my LAN, but I don't mind the speed myself. And I find it part and parcel of the retrofun I have with them: my Thinnet segment has 2 SGI Indigos on one end, the 68030 NeXT Computer in the middle, then the BNC connection on a CentreCOM hub to the rest of the LAN, and a Sun SPARCstation IPC on the other end. Yep - I use actual coax, AUI's with BNC connectors (& the BNC on the NeXT) and terminators. Mucho fun.
Another Austin area NeXT fan! Welcome. I believe I finally have my Turbo Color fully operational (although, not the display). Wonder how many of us there are in town...
We should start a NeXT user's group in Austin Texas! NUGAT!
Quote from: zombie on May 24, 2022, 08:46:09 PMWe should start a NeXT user's group in Austin Texas! NUGAT!
You're on!
Quote from: crimsonRE on May 23, 2022, 08:30:45 PMGranted that I don't need to shuttle around much data to/from my NeXTs on my LAN, but I don't mind the speed myself. And I find it part and parcel of the retrofun I have with them: my Thinnet segment has 2 SGI Indigos on one end, the 68030 NeXT Computer in the middle, then the BNC connection on a CentreCOM hub to the rest of the LAN, and a Sun SPARCstation IPC on the other end. Yep - I use actual coax, AUI's with BNC connectors (& the BNC on the NeXT) and terminators. Mucho fun.
I don't have any other AUI kit. I have no BNC kit left for 20+ years now. The whole house is 10G cat7+... I do have a serial 'network' for the dumb terminals, but we won't talk about that!
Fellow Austin user checking in. Welcome to the forum!
Thanks for introducing it to me :P
Oh, hey, I can see attachments now! And my comments aren't individually reviewed by an admin!
I've been promoted to "probably not bot, might be human"!
Hello Dave: Welcome aboard Best Regards Rob Blessin
Quote from: Rob Blessin Black Hole on May 26, 2022, 07:06:12 PMHello Dave: Welcome aboard Best Regards
Thanks Boss!
I had a good look at the internals of the NeXT PSU and it's a bit of a pig. The way it is put together makes it a bit unfriendly to work with. I don't think I can put a cap replacement kit together for it because the average person on the street isn't going to be able to do it with any degree of safety. I'm still going to have a good, solid look at designing a more modern replacement PSU.
Work on the DSP RAM card is going well.
The SCSI implementation on the NeXT is built into the PC chip.I don't yet know how conformal it is with standards from the CPU side, how the registers look, etc, but it looks doable to add a secondary SCSI interface that is faster and wider.
I've recapped a trio of NeXT cube PSUs and found it to be a difficult chore --- also, I think some of the caps were special-order from Chemi-Con and had values I couldn't find. IIRC they were smoothing caps on the primary side just past recification, and replacing them with a near value appears to have worked.
Meanwhile, the NeXTstation PSU seemed even more challenging; after taking a good long look at it, I decided that I'd rather employ a watchful waiting (
https://en.wikipedia.org/wiki/Watchful_waiting) approach than try to dig in. I forget quite what was the problem I ran into, but I do remember that everything was quite densely packed.
When you say that the average person on the street won't be able to do it safely, are you talking about safety for the device or for the technician?
(PS: I'm grateful that someone with your experience has decided to dive into NeXT hardware hacking!)
I'm saying that the pizza box PSU is interestingly folded up in a way that makes have a go repairs/recaps unlikely to be safely completed for the power supply and the system. It is at least a modular system for the three power rails. The power_good/reset circuitry is arcane. I think it should be left to experts, and recap kits shouldn't be in the hands of people unless they fully understand what they're doing.
Hi side cap substitutions are fine - go with the next higher values and you won't go wrong.
On the Cube PSU, I see two major versions. One has a configured fault condition for no-load on -12V that shuts the PSU down - the other has that feedback circuit revised. I have seen suggestion of using a dummy load resistor to prevent the shutdown. I think it would be more elegant (and cooler) to rework the load fault circuit to allow the -12V rail to just hum along on its minimum drive level, as that is needed for serial to work correctly. I have a couple of Cube PSUs coming and I'll see what there is to see.
If there is one NeXT thing that could really use a cap kit, should it be considered within reach of the just-bought-FR-301-wielding weekender buckaroo, then it is the analogue board inside the MegaPixel display. In mine, it was home to some of the dampest, fishiest ELNA "Long Life" something-thousand uF capacitors that I've ever encountered in my lengthy "have a go" recapping career.
I have two of those. One weighs about twice what the other does. I'll take a look.
When I retire in some years I shall have the time to take on the task of re-capping my various machines/PSUs - likely will need to start with the Macintoshes, and SGI PSUs. Hopefully the regular exercise I give the machines, and the fact they live in a cool, dry basement computing cave will prolong their lives until that time. My MegPixel displays are doing quite fine.
Fantastic to have someone with deep knowledge of electronics onboard, along with Brian et al. Do keep the details coming! Perhaps put them in the NeXT Work Logs section (I do see your post there about work on the NeXTDSP)...