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PC532 Gerber files

NobodyIsHere

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Hi
Does anyone know where to find the Gerber files for the original PC532 home brew computer? I have looked in all the obvious places. If someone knows any of the original PC532 hobbyists or has sources that would be helpful. Thanks, Andrew Lynch

http://www.thefullwiki.org/PC532
 

cruff

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I had an original PC532, but do not recall ever seeing the gerbers, as I was part of the group board purchase.
 

NobodyIsHere

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Hi
Are you still in contact with other PC532 owners? Do you still have your PC532?
 

cruff

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Hi
Are you still in contact with other PC532 owners? Do you still have your PC532?

I haven't heard anything about the PC532 in quite a while. I do not have mine anymore, which I regret.
 
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NobodyIsHere

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Something is not right. I think the ET532 and PC532 are two separate different projects. The ET532 plugs into the PC532 backplane SCSI expansion connectors. It may very well have its own CPU (smart peripheral) since the PC532 backplane connectors are 62 pad card edge SCSI connector (not XT ISA) which the ET532 is attached.

There are photos of the PC532 here: http://cpu-ns32k.net/PC532.html It is a Baby-AT format PCB not an XT ISA board.

Also, there is a description here of the PC532 Gerber files which is different than the ET532 Gerber files

Take a look at the PC532 schematic, it is a very unusual design which leverages parts of the PC/XT/AT format but not all. Mostly case & power supply.
 

eeguru

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The et532 is a complete SBC with SCSI (even though it looks like an ISA card edge), Ethernet, and 16 serial ports. Here is the converted schematic:

https://www.retrotronics.org/N8VEM/et532_schematic.pdf

I'm just trying to help. Either you or Dave said the old gerbers were unreadable in the tools your were using. ViewMate Deluxe loaded them just fine. I had to define some apertures in order to re-export. But it seemed to do the job. y/w
 

NobodyIsHere

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Thanks for the help. I will download the updated ET532 schematic & Gerbers tonight.

I think PC532 and ET532 are using SCSI as a literal expansion bus instead of ISA parallel bus. Normally its just for hard drives, CDROMs, floppy drives, etc. but in this case it's whole SBCs.

Check out the PC532 photos at the link above.
 

eeguru

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It appears so. This page sums things up nicely:

http://www.netbsd.org/ports/pc532/faq.html

The PC532 Gerbers may be lost forever unless they are sitting in a private collection - likely on some 5.25" diskette that is rotting as I type :(

If you do find them, I was able to convert with ViewMate - FYI. I was able to import them into Eagle afterwards.
 

NobodyIsHere

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It appears so. This page sums things up nicely:

http://www.netbsd.org/ports/pc532/faq.html

The PC532 Gerbers may be lost forever unless they are sitting in a private collection - likely on some 5.25" diskette that is rotting as I type :(

If you do find them, I was able to convert with ViewMate - FYI. I was able to import them into Eagle afterwards.

That's precisely my fear. PC532 is the first, if not the original, open source, open hardware project and probably the best documented most successful project like it AFAIK.

I wish any of my projects ever even came close to what they were able to achieve in 1989. It is quite an accomplishment and I hope the Gerbers aren't lost to history.

Our best hope is to ask around to former PC532 owners, FTP mirrors, pack-rats, or other interested people to see if they scooped up the PC532 Gerbers. Maybe even by accident.

Given the size of the files, I'll bet its rotting away on some ancient backup tape or disused hard drive. I tried posting on usenet comp.sys.nsc.32k but it is not accepting posts anymore (at least from Google Groups) last post in 2008. I think CCTALK would have the best chance of people who remember PC532 and I'd ask there but I haven't been a member on the mailing list for years.
 

NobodyIsHere

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following up on this, we did finally find the PC532 Gerber files. Unfortunately they were in the older RS-274D format and lacked necessary information to convert them to modern RS-274X without significant manual editing. I think we have all the information for conversion but it would require specific knowledge and capabilities. It seems the conversion problem centers on lack of a Excellon drill file, sizes of drills, pad sizes, etc.

ftp://ftp.berklix.com/pub/pc532/gerbers/pc532/

ftp://ftp.funet.fi/pub/misc/pc532/hardware-docs/pcbinfo/

If anyone is proficient in editing Gerber files and is up for a challenge please let me know.
 

eeguru

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I pulled them into Eagle, recaptured the board layout, cleaned them up a bit, and regenerated them from a real board layout. They all pass DRC and a mask comparison with the originals. I'll recapture the schematic eventually. But at this point I don't have any reason to doubt they are less than 100% electrically compatible with the originals. The silk-screen is only about half redrawn, but it looks good.

https://www.retrotronics.org/N8VEM/pc532_eagle.zip

Good luck
 

NobodyIsHere

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Wow, that's great news! Thanks! I take a closer look at these later tonight. Much appreciated! Andrew Lynch
 

NobodyIsHere

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Hi, were you able to integrate the drill file information in to the new Gerbers? I can't see the Gerbers at the moment but as I recall there was an issue with pad size mismatch. I wonder how you were able to fix that? Did you enter the dimensions for the pad types manually or did Eagle figure it out on its own? Thanks, Andrew Lynch
 

eeguru

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I placed pads, vias, and non-plated drills manually using the copper relief as a guide; but mostly based on the context of the hole. That link includes a new Excellion drill file (.TXT).

For example, the vias I placed are much smaller than the originals so they can be tinted.
 

NobodyIsHere

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Interesting. I use KiCAD and it just cranks out the Gerbers at the very end of the PCB design process before going to production. I've never done much with them other than to make sure its making all the right layers. Time to take a closer look!

Thanks, Andrew Lynch
 

eeguru

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I did just find an oversight in the work I did yesterday. Their original eCAD tool did not generate thermal relief for ground pins associated with connectors. So I missed those ground ties until I started looking at the schematic today. Let me know if those first set of files look reasonable. If so, I'll regenerate a new set with the fixups as I find them (ATX supply header maybe?).

Interesting the 62 pin card edge connectors had ground down most of one side with no thermal wagon-wheels. It must have been difficult to solder those first runs of boards...
 

eeguru

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It looks like the SCSI connector, 62-pin card edge connectors, and UART connectors were the only ones missing ground relief.

After reviewing the schematic some more, I have also found what I believe to be an oversight in the original design. There is a net called +V (different than +5) that is tied to various unused active low inputs on devices. It is actively routed around the board rather than merged with the +5 that is an inner layer fill. I suspect one would only do that if you wanted to couple +V and +5 through a 20-100 ohm resistor (+V has 20+ loads) for safety. However I cannot find anywhere in the schematic nor board layout where they are electrically coupled. I'll add a resistor location so one can couple them either with a jumper or actual resistor.
 
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