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saybur

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Everything posted by saybur

  1. It should be significantly faster. AppleTalk caps out at 230.4kbits/sec, so maximum throughput on that should be something like ~28 kilobytes per second. You do have me wondering though, so I'll check and see how this performs vs. the real Nuvolink SC and a NuBus Ethernet card and report back.
  2. I've been spending some time recently making a SCSI to Ethernet adapter using all-new hardware. I managed to snag a Nuvotech NuvoLink SC off eBay, and after doing some analysis of how it talks with the driver over SCSI, I've decoded the vendor-specific parts of the communications protocol and implemented a compatible version on a custom PCB. Here's some pictures of the board and test setup: https://imgur.com/a/ZJFfrSG The board is based on a ENC28J60 Ethernet chip and XMEGA AU series microcontroller, with a SD card thrown in the mix for good measure to emulate a hard
  3. Yeah, the 110ohm resistors are definitely getting harder to find. SCSI allows an alternate configuration using 100ohm packs and dropping the terminator voltage to ~2.63V or thereabouts, if you want to try that in the future.
  4. I've made clones of the v4 hardware design. Some advice if you want to go down this route: 1) I had to roll my own PCB layout: the 74F06 chips used as bus buffers are now obsolete, and I wasn't able to find a part with a matching footprint. The 74F126 is signal compatible, but since it only has 4 elements per unit, you'll need at least 5 of them instead of the 3 '06s in the original design. There aren't all that many open collector/open drain ICs able to sink ~48mA these days... 2) The best way to program the boards (IMHO) is grabbing yourself a Cypress CY8CKIT-059 dev boar
  5. That controller board is the most problematic part of the Sony PSUs in these models, in my experience - I've got one that even after recapping and cleaning it does the whole "shut down, then boot right back up again" that you're describing. That one looked just like yours, nice and gunky, with some pretty bad trace rotting. On the plus side, the PSU itself works fine - it seems to just affect the power-down circuitry.
  6. Looks like the 8-Bit Guy on YouTube just got one of these as well: https://youtu.be/nDmNAz8yQ7Y?t=3m10s It's hard to see, but it does appears to have the sticker and the generic front case printing.
  7. Adding some more pieces to this puzzle, I found another one of these oddball Performa 475s. Pictures are here: https://imgur.com/a/dGszw This one came with the original packaging, showing it was originally sold at Best Buy as part of one of those all-in-one-box Performas. The picture on the box conveniently shows the way the system is supposed to look, so I imagine the original owner may have been a little confused when they popped the thing open to discover this beaut inside. Here's the serial number decode: Same week of production as unity's, separated by a few thousan
  8. I believe internal SCSI on (all?) non-portable Macs provides TERMPWR, fused on the logic board. The schematic for V4 of the SCSI2SD has J3 connect +5V through a diode right to the SCSI TERMPWR line, which sources power to device terminators if the main board fuse is open. I don't have the V3 schematic, but I imagine it's set up the same, it's in line with the way the SCSI spec talks about it. Maybe check if the IIsi board has an open fuse? Or check the input voltage on U2 (right leg, the one with the cap) without J3 shorted, might be that the line is sagging below the ~1.1V headroom on
  9. Mine run fine with just the USB cable, but I have had problems before when a SD card is not present - do you have one installed? Also, what platform are you running it on? In the past, I've had to diagnose problems using the scsi2sd-monitor utility, which has no documentation that I was ever able to locate. For that one, investigating the source was required (and adding some debugging statements).
  10. Pulled the heatsink off and after cleaning off the residual grease, saw a discoloration between two halves of the die, one half hued purple, the other blue: https://imgur.com/a/kpHiU It sadly matches the description given for a cracked 6100's 601 here: https://68kmla.org/forums/index.php?/topic/28904-dead-6100/ So, that's probably it. I'm guessing I fouled up, either with too little grease (it looked a tad dry on one side, IMHO), pushed too hard when re-applying the cooler, etc. Sigh. Anyone have a second opinion? I'd love to be wrong!
  11. I don't think so, but that's a good idea, I'll double check. The stuff I used is (theoretically) supposed to be non-conductive, but I'd rather not rely on that saving my bacon. Also, thanks Macdrone, I'll also double check the power supply in circuit to see if there's anything wonky. I don't completely understand the PS On-Off / PFW line from the PSU, but here's a shot: 1) it's connected to the +5V trickle to start the system 2) is pulled low by the Mac to signal the PSU to shutdown (?) Does anyone know if it is monitored in any way as a power-good signal? Or is that generated
  12. Oh, and mods, sorry, this should obviously be in the NuBus category. I'll try to actually read the category before submitting next time
  13. I've got a problem child Power Mac 7100/66AV that I've been trying to fix for a while, and was hoping for some thoughts from knowledgeable people here about the next steps to take. The issue: from either an ADB keyboard or the rear button, the system powers on (front LED lights, there's a slight "click" from the speaker, PSU fan spins up), but then nothing happens - no chime, no video, zilch. When I first got this system, it worked fine; it had been in climate controlled storage and was apparently treated well beforehand, so fairly clean, no obvious cap issues, etc. I replaced the PRA
  14. Sparkfun used to sell this, which would make for a pretty sweet stockalike mouse with much better tracking behavior. The software could be modified by removing the serial communications code and plugging in sensor tracking logic instead. It'd definitely be a project: code for that + custom PCB + actually finding some sensors, which don't appear to be sold anymore. Definitely should be doable though. I figured someone would be interested in gutting the serial component at some point, so the software is already set up for that kind of modification. https://www.flickr.com/photos/raneko/42
  15. The Java software is in a usable state for Linux desktops. See https://github.com/saybur/trabatar. Enjoy something along the lines of Synergy, but for vintage Macs Take a look here for hardware instructions involving an Arduino. Long term, the goal is to get this working on a Raspberry Pi with a custom PCB shield that includes a level shifter IC (like the MAX3232). This should let you both control the system and browse your local network/Internet with the serial line. Work is proceeding on that front: plenty of other people have done similar things, so it should hopefully go prett
  16. Inspired by bmow's work, I've created a generic Apple Desktop Bus device transceiver using Atmel AVR microcontrollers. The goal is to make it (relatively) easy for the hardware hackers here to integrate ADB support. Take a look at the GitHub repo if you're interested in playing around with the code: https://github.com/saybur/trabular Mouse and keyboard support work. I threw together a quick Java program on my computer that bombs my Arduino with the serial control codes, which then sends them to the Mac. It functions pretty well for a kludge. Also note: it's trippy to control a Mac
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