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Working on a couple of SMC-70s

M

marcoguy

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I've finally gotten around to working on the two Sony SMC-70s that arrived on my doorstep a few months ago.

Probing the mono composite out port on one machine, I found the video signal on the center pin of the 8 pin DIN socket. No idea what the other 7 pins are for, aside from maybe a speaker output.

Once I was able to connect a monitor, I found that the unit with a bad keyboard (a couple busted key switches) had good RAM, while the unit with a good keyboard gave a memory error on boot.

So, one keyboard swap later, I've got a working unit and a parts rig. Only, I have no documentation or software. The machine boots into a system monitor, and from some fiddling I've discovered that pressing the B key in the system monitor loads a Sony BASIC interpreter from ROM.

That's about as far as I've gotten with this box. I haven't found any manuals or software online, the closest I got was this site, but unfortunately the original site is down and the software wasn't archived.

So, if anyone has a manual they wouldn't mind scanning, or software they wouldn't mind imaging, I would really appreciate it. I hope to be able to get this system up and running with CP/M, preferably in color if I can find the pinout of the DB25 RGB connector.

And for anyone interested, here are a couple pics of the current setup:
IMG_20170101_153335.jpg
IMG_20170101_153349.jpg
 
Dave Dunfield has archived an SMC70 boot disk here

The SMC-70 is kind of special in the firmament of CP/M machines. Not only was it the first to use 3.5" floppies OA-D32 drive manual here, but it had a plethora of options, including ROMS for Kanji character support, Genlock option with video titling software, and even an add-on 8086 box that enabled it to run MS-DOS. It was expensive, alas--and a bit late to the PC scene. It was also only one of two CP/M systems to run VisiCalc.

You'll find the floppies quite a bit zippier to use than standard 5.25" fare because the drives in these boxes (as well as early HP boxes) spin at 600 RPM, not 300 RPM. I was involved in a US outfit to equip their portable CP/M box with the OA-D32 drives at around the same time--it was called the "Preis PC" and I even coded for the MFM HD controller. It was a contract job and I never knew what became of the company. I still have the BIOS source listing, however.

When the SMC-70 came out, there was a war of the "pocket floppy" formats. I still have the 3.25" Dysan floppies and drives. To the best of my knowledge, they only saw commercial use on the Seequa Chameleon 325--and most likely, any survivors have had the drives replaced with regular 3.5" DSDD ones. I think Shugart and Dysan were in the 3.25 camp, while Sony and HP were in the 3.5" one.

Congratulations on your acquisition.
 
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Thanks for the links and the info. That CP/M boot disk was just what I was looking for.

I had read about the 600 RPM drives, they do make a pretty noticeable difference. I was a little surprised that the drives in my system are working well after all this time, albeit with some mechanical issues when loading or ejecting disks. A drop of lubricant and they're working like new.

I wasn't aware there was an 8086 add-on for this machine, sure would be nice to come across one of those some day. All in all this seems like a great little CP/M box, and I'm glad to add it to the collection.

And again, if anyone knows where I can find software or manuals for this system, it would be a big help.

IMG_20170101_233828.jpg
 
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The default colors are white text on a dark green background.
Use SETUP to select something more legible on your display.
Try white text, black background and black border.

HTH,
Andy
 
Chuck, is new or NOS 3.5" media still available for this system anywhere?
I think it originally used Sony OM-D3320.
 
I probably have a collection of manuals and software, I'll check what I have and scan it in if you're still looking for it.
 
markgm said:
I probably have a collection of manuals and software, I'll check what I have and scan it in if you're still looking for it.
Click to expand...
Apologies for necroing this thread, but did you ever manage to find any manuals or software for this machine in your collection? Asking as I, too, have an SMC-70, and would like to get it working as well. :D
 
mondoshawan said:
Apologies for necroing this thread, but did you ever manage to find any manuals or software for this machine in your collection? Asking as I, too, have an SMC-70, and would like to get it working as well. :D
Click to expand...
Is there anything specific you're looking for? I started to inventory what was released for this system (tabs are at the bottom - https://docs.google.com/spreadsheets/d/1edZfjsRuWKsI13HDt1HEsuDTW6KDFdtY2DM2cHE6DB4/edit?usp=sharing), but that's as far as I got as other projects took over. I'm not sure the best place to catalog this stuff, but I might add it to the Wikipedia page for the machine (I've written a lot of it already).
 
Specifically looking for a service manual, if possible, and the pinout for the RGB multi out (like the original folks that started this thread were after). I have the right Trinitron at this point, just need to make a cable for it. I suspect mine might have some trouble, though, given past probing of that connector.
 
Okay, so, I found (what seems to be) the only copy of the owner's manual and the service manual on the 'net. I hate to link it, since it seems like a scummy site, but it's at https://www.manuals-in-pdf.com/download-SMC70-SONY-p-473259.html and https://www.manuals-in-pdf.com/download-SMC70GP-SONY-p-292480.html for $50, *each*. Doesn't look like Sony still has the manuals available, as you indicate in your spreadsheet -- totally couldn't find it anywhere.

I'm going to archive a copy of it and the owner's manual locally so I can bring this thing up. FWIW, the multi-out connector on the SMC-70 uses a common ground for all of the signal pins for RGB Vsync and Hsync, weirdly, despite them likely needing to be coaxial connections. Personally, when I build this cable, I'm going to pair up the grounds per channel because it's good practice, but schematic-wise, it apparently doesn't matter. Basically, this is the bit of the reference manual you need if you want to wire up an RGB -> VGA connector:

Screenshot 2023-05-12 at 12.19.51 PM.png

Of note are pins 1 and 5 (RGB/#COMP and 625/#525, respectively). These *look* like inputs, but I don't think they are, in actuality. They connect to this bit of schematic:

Screenshot 2023-05-12 at 12.43.27 PM.png

Those are outputs from a set of inverters, which further come from the outputs of an 74LS259 latch, so I don't *think* you need to do anything with them to wire up VGA. In my digging, I found several schematics that try to drive voltage into these pins, but after scanning through this schematic, I don't think that's actually necessary.

If black and white composite output is more your speed, pin 8 on the DIN connector is your friend. Sony didn't bother trying to mix the colors using the R2R DAC used for the RGB pins on the multi-out connector, unfortunately. The other pins on that DIN connector are:

Screenshot 2023-05-12 at 12.58.04 PM.png
 
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If anybody still has physical manuals, it would be good to try to get these things imaged properly. The service manual I linked has the entire BOM, schematic, and board layout for this machine, so it should be possible (modulo any GALs or ROMs, of course) to make a new machine from it. The copy of the service manual on that site isn't 100% great -- image quality is a little low in places, so it would be good to re-scan and hand off to bitsavers or archive.org. Not sure about the licensing for the PDF I downloaded, so not comfortable just uploading that one.
 
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I had good success connecting the RGB output of my SMC-70 to an Extron HDMI-300A scan converter. Some CRT and LCD displays may be capable of displaying it directly.
 
Perhaps seeing the other end of the will be of some help as well. I didn't list the service manuals in my spreadsheet as Sony didn't typically sell those to consumers, but I can add them.

video.jpg
 
shirsch said:
Do you know anyone with a large-format scanner? It would be great to have a PDF of the service manual.
Click to expand...
I don't, but I'll check if a library around me has one I can use.
As an aside, did someone here pick up the SMC-70 that was listed on ebay by Goodwill? It would be handy to have a scan of the price list binder that was a part of that auction.
 
That would be great if you can find a scanner. The photos you sent me last year were very helpful, BTW. I was able to get a Gotek/Flashfloppy drive and scan converter working with the SMC-70.
 
Maybe contact Bitsavers? Al doesn't have any of these manuals up there, and probably should. :p
 
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