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Mystery S-100 FDC, VISTA, SOL

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    Mystery S-100 FDC, VISTA, SOL

    Looking for any information on this Vista FDC.

    It came with a SOL-20 and 2 MPI b51 SS full
    height floppy drives, also tagged Vista.

    I have zero information and no boot diskettes.
    Most of the IC's are late 1979 datecode on the
    controller and there is no 40-pin controller chip.

    This will be my first attempt at attaching a photo here...

    Any info appreciated.
    Attached Files

    #2
    Vista was a company that made accessories and (Orange?) clone parts for the Apple, and S-100 computer market. It was owned by the same brothers who owned ACP (Advanced Computer Products), a early computer store. Vista made apple clone computers, apple accessories, S-100 accessories (like expansion drives and drive enclosures), and some software was branded with ther name.

    Much of the stuff they sold was unlicensed/unauthorized copies of legitimate products. Some of the stuff was decent quality, some was very crudely made.

    At one time, the headquarters for Vista was on Edinger directly across the street in Santa Ana, CA from the original ACP computer store, where one of the first computer swapmeets was held in the parking lot. The ACP computer store was sold a few years ago, and Vista declared bankruptcy and was liquidated decades ago (after being sued successfully by multiple parties, and owning Millions $$$ of dollars), although new products that were shipped to Vista by other computer manufacturers, that were never paid for by Vista, or recovered by the Bankruptcy Trustee or the Legal Owner/Manufacturers surfaced for years, reappeared and available for sale from where ever they were hidden from the Bankruptcy Trustee.

    The Brothers who owned ACP actively solicited donations for their computer museum (which was housed in some backrooms at the ACP store), and in the past few years have been slowly selling off the stuff that was donated to the museum on eBay.
    Last edited by MicrocomputerSolutions; December 15, 2017, 03:54 AM.

    Comment


      #3
      Thanks much for that background info.

      Looks like I will end up 40 IC's to the positive.

      The drive cabinets are not in bad shape, although the power supplies work, like you said, the PCB layout is of low quality.

      On the positive side, I purchased a Rev4 Sun keyboard and harvested the keytronic foam pads and disks. The keyboard was in excellent shape, barely used if ever. I spent about an hour disassembling the keyboard yesterday and another hour today pulling off the disintegrated foam and disks from my SOL keyboard. The new pads were a snap to put on and now everything that wasn't working in relation to the keyboard now is working great. I started by actually pulling off the keycaps and realized I didn't need to at all...just remove the old discs and foam, blow away the small bits and stick a new one on the key..a pencil eraser pops them on and done. I started replacing them row by row and it really was a snap. Before assembly I took some dry 400grit wet-n-dry sandpaper and used it dry very lightly and sparingly on the keyboard FR4 pads...then a flux remover spray. I recommend this method. Most useful tool is the small screwdriver that comes with iPhone repair kits for popping out the old discs and the pencil eraser for tapping the new ones in place...I can't imagine punching out foam, then manually glueing. That keyboard I harvested parts from cost about $25...well worth it...and I still have some left over pads.

      Comment


        #4
        If they were in the bootleg/clone/knockoff business, judging from the density and lack of FDC IC, it's probably a North Star compatible board, which was hard sectored 5.25" disks, 10 sectors per track. I would guess, again from parts density, that it would be the double-density North Star controller. North Star disk systems were popular and common, especially on early S-100 stuff.

        The other popular discrete controller from the era was the Micropolis disk system controller, again hard sectored 5.25", but using 16 sector disks instead of 10 sector disks. It'd have to be a modified Micropolis design though, all of the Micropolis controllers I've seen have trimpots for final adjustment.
        Check out The Glitch Works | My Retro Projects | Vintage Computer Services | Glitch Works Tindie Store -- Vintage Computer Kits and More

        Comment


          #5
          Originally posted by glitch View Post
          If they were in the bootleg/clone/knockoff business, judging from the density and lack of FDC IC, it's probably a North Star compatible board, which was hard sectored 5.25" disks, 10 sectors per track. I would guess, again from parts density, that it would be the double-density North Star controller. North Star disk systems were popular and common, especially on early S-100 stuff.
          Northstar profile doesn't successfully decode a Kryoflux image of a Vista disk for the Sorcerer in HxC though

          Comment


            #6
            Originally posted by glitch View Post
            If they were in the bootleg/clone/knockoff business, judging from the density and lack of FDC IC, it's probably a North Star compatible board, which was hard sectored 5.25" disks, 10 sectors per track. I would guess, again from parts density, that it would be the double-density North Star controller. North Star disk systems were popular and common, especially on early S-100 stuff.

            The other popular discrete controller from the era was the Micropolis disk system controller, again hard sectored 5.25", but using 16 sector disks instead of 10 sector disks. It'd have to be a modified Micropolis design though, all of the Micropolis controllers I've seen have trimpots for final adjustment.
            Looks like your Northstar intuition is correct. Please see snippet from a 1985 newsletter article. Keywords: Vista, Micropolis, 100TPI

            Comment


              #7
              Originally posted by bcc View Post
              ..just remove the old discs and foam, blow away the small bits and stick a new one on the key..a pencil eraser pops them on and done. I started replacing them row by row and it really was a snap.
              That was fortunate. A % of the SOL-20 keyboards, probably the earlier ones like mine, the foam disks did not click into position, but were attached instead with a contact adhesive to the bottom of the key plunger. In my case to reattach the foam disks, I used ultra thin double sided tape (punched into disks) because I didn't want to put any liquid adhesives near the assembly. Generally its not necessary to clean the PCB surface in any way, provided that is, that you have the correct metalized mylar film discs, like the ones from the Sun, these raise the capacitance well above that required to trigger the key detect circuitry.

              That disc controller to me looks very similar to a Northstar MDS-AD3, with roughly about the same number of IC's, from what has been said it may be a fairly close knock off, it would be interesting to compare the schematics if you can find the Vista one.

              Comment


                #8
                Originally posted by Hugo Holden View Post
                That disc controller to me looks very similar to a Northstar MDS-AD3, with roughly about the same number of IC's, from what has been said it may be a fairly close knock off, it would be interesting to compare the schematics if you can find the Vista one.
                Have not turned up any docs yet. The OP's card is S-100 but Sorcerer newsletters suggest the Vista system sold in Oz interfaced directly to the 50 way connector.

                Comment


                  #9
                  Originally posted by exidyboy View Post
                  Have not turned up any docs yet. The OP's card is S-100 but Sorcerer newsletters suggest the Vista system sold in Oz interfaced directly to the 50 way connector.
                  This Vista board has about 50 TTL's and a 34 way drive connector, two regulators one Xtal etc. The MDS-AD2 & 3 had about 47 IC's the 34 way connector and it had 3 ROMs on it.

                  I wonder if there are thee ROMs on this vista board ?

                  If it was essentially a knock off, then the OP might get lucky if the schematics are nearly the same. The MDS boards I got were both faulty and needed repairs and I needed the schematic. One way would be to count and compare the IC types that are there, to see if they were close to those in the MDS manual.

                  Comment


                    #10
                    Originally posted by exidyboy View Post
                    Have not turned up any docs yet. The OP's card is S-100 but Sorcerer newsletters suggest the Vista system sold in Oz interfaced directly to the 50 way connector.
                    A 1981 newsletter clears up the confusion as to how it can simultaneously "S-100 free" and yet an S-100 card.

                    The Vista E-20 system for the Sorcerer consisted of a DELTA double-density controller card and an interface board to the Sorcerer and MPI B51 drives. So the controller is S-100 but somehow they adapt it directly to the Sorcerer without requiring the Exidy S-100 expansion chassis. I imagine the enclosure must be pretty big!

                    Apparently docs were provided with controller schematics and theory of operation but I can't find them anywhere online or in the catalogues of the key computer museums.

                    Some encouraging progress has been made by people much more knowledgeable that I on figuring out the MFM sector encoding.
                    I have about 15 discs that look like they would be readable. Some are rather warped having been under a house for who knows how long.

                    Comment


                      #11
                      Originally posted by Hugo Holden View Post
                      I wonder if there are thee ROMs on this vista board ?
                      I can't see any ROM's in the OP's photo but I don't know for sure that the discs I am working with were written with that board.
                      It is possible the S-100 to Sorcerer interface board held an EPROM. I will look through old newsletters today and see if there are any clues.

                      Progress has been made (not by me) on the MFM 250Kbit/sec disk encoding and attention has now turned to the checksum algorithm.

                      The Theory of Operation documentation or ROM images would make life so much easier.

                      Comment


                        #12
                        Originally posted by exidyboy View Post
                        It is possible the S-100 to Sorcerer interface board held an EPROM. I will look through old newsletters today and see if there are any clues.
                        According to an article in a 1980 newsletter there is a boot ROM.
                        Typically at B900H for a 32K machine or D900H for a 48K machine (which meant you could no longer use your ROMPac).
                        I don't believe this ROM has been dumped so I'll add that to the long list of Sorcerer material that has to be tracked down.

                        Comment


                          #13
                          Originally posted by exidyboy View Post
                          I can't see any ROM's in the OP's photo
                          The reso of the photo is not good enough to be sure, the three ROMs on the MDS cards just look at a glance like the rest of the TTL IC's there, but looking closely at the IC type and a small additional markings they are Roms.

                          Comment


                            #14
                            Checksum algorithm has been reverse engineered by Simon Owen in spite of a complete lack of technical information.
                            Larry Kramer has been tasked with fine-tuning the cpmtools definition.

                            Comment


                              #15
                              Dutchacorn - who used to own a Vista controller for the Sorcerer - has confirmed that the board pictured by the OP is the same as the one he had.
                              Now we just need to find one, photograph it, dump the ROM's/PROM's and scan all the documentation.

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