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Recapped Quadra 605 in rackmount case a success!

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It seems that none of my Centris and Quadra era machines are stable anymore unless they've been recapped. In the last few years I've recapped several motherboards, but even they started showing issues, so now I'll be recapping or replacing power supplies, too.


After recapping my 1U Amiga 1200 (which is now running 100% perfectly without panics or core dumps for more than a month), I was inspired so I decided to do a Quadra 605. Since I have more motherboards than cases (the plastic is SO brittle!), and since I don't have the capacitors I need for the power supplies, I decided to build the recapped motherboard in to a 1U case and use a standard power supply that fits the case:

Whole machine


The Quadra 605 motherboard has had the resistor swap to overclock it to 33 MHz. The CPU is a full m68040 with the heat sink attached using Arctic Silver thermal adhesive epoxy and I added two AAA batteries in place of the 1/2AA. And, of course, it has a 128 meg SIMM and a pair of 512K VRAM SIMMs.


For storage I installed an SCM PCD-50B SCSI multi-card reader. It's limited to async negotiation only, but since Mac SCSI isn't all that fast anyway, it still makes for a very snappy system. It presents each card slot as a separate LUN which Mac OS apparently ignores but NetBSD is happy to use. It's pictured with just one 64 gig CompactFlash in the PCMCIA slot with an adapter (which must be in that slot because the PCMCIA slot is LUN 0, and the Mac won't boot off of a LUN other than 0), but I also added another 64 gig MicroSD in an SD adapter in the SD slot for a total of 128 gigs. If I need more later, I may add yet another 64 gig MicroSD in a Memory Stick PRO Duo adapter, which in turn installs in an adapter to make it fit in the standard Memory Stick slot. I've tested it and it works. Plus, the CompactFlash is in the PCMCIA slot, so I can add another CompactFlash, too. The SCM PCD-50B are neat adapters :)


SCSI multi-card reader


The power is attached through a simple SATA power cable which provides just 12 volts and 5 volts. I can't imagine that much would make use of -5 volts, but the speaker output doesn't work and I'm guessing the serial port may not. I'm waiting for some 7905 regulators to be delivered so I can add -5 volts soon.


Wonderfully simple power


After running it for several weeks compiling non-stop, I think it's safe to say that it is completely and perfectly happy. Next up is the Quadra 610 with 264 megs of memory and a 50 MHz NewerTech Quadra Overdrive...



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Back in the early 1990s someone gave me a Mac Classic with a (physically) broken screen. I found and ordered a new tube, but that came in the mail broken. So, instead, I built the motherboard in to a little PC tower case and made a TTL adapter with just a 74LS14 (Schmitt trigger inverter). I used it for papers and stuff all through college. An old PC TTL monitor should be much easier to find than an appropriate scan converter.


Interestingly, Macs in PC cases back then were called Hackintoshes ;)

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9 hours ago, mactjaap said:

I found this but not sure if it works on a Plus....


I think horizontal sync and video get inverted and vertical sync goes straight through. All you need on the 9 pin for the monitor is:


1: ground

7: video

8: horizontal sync

9: vertical sync


No idea where you get the signals from on the Plus, but that shouldn't be hard to find. Ground any unused inputs on the 74LS14, add a small capacitor, and that should do it!

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5 hours ago, BadGoldEagle said:

.  .  .  outputs a signal with an oddball horizontal refresh rate that most monitors/projectors can't hook up to.

Cat Mac/Hacintosh TTL output was fine in a an IBM 5151/Hercules Graphics world on available, inexpensive displays. Herc overlapped analog display interface development and then beyond for more than a few years.


Compact Mac video -> TTL -> 60Hz VGA conversion would be the way to make use of these ancient adapter setups I would think. Some combination of existing adapter technologies prototyped and then produced in this newfangled 10cm x 10cm PCB form factor would be a great project.

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On 1/20/2018 at 3:57 AM, johnklos said:

An old PC TTL monitor should be much easier to find than an appropriate scan converter.


You'd think, right?  Rare as hen's teeth around here, and they go for a packet when they do appear.

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yea your right TTL monitors are difficult to find. I have ONE, and its part of a Delta Gold Elite XT machine that I own, which actually is a Hercules monochrome setup. 


As far as hooking the Plus/SE/SE30 to a modern 60Hz scanning setup you would need a scan converter. 


Which actually "could" be as simple as an FPGA with dual-port video RAM. Or, standard SDRAM with a "dual-port" controller in the FPGA. At that point the computer could write the video data into the RAM, while you have another clock that reads from RAM and outputs at VGA frequency. it would still have a TTL/CMOS output so youll be black and white of course. 


Also you CAN hook up flat panels to these boards, as long as they are parallel displays with scanning/clocking for each individual pixel. Most more modern displays are 4, or sometimes 8 pixels per pixel clock. instead of a single pixel per pixel clock. 


You would need the pixel clock which on an SE/30 is easy to get as its the clock the runs the UE8. 

Edited by techknight
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