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New CoCo 2 owner

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    New CoCo 2 owner

    Hi folks, couldn't afford a CoCo 3 as they are now over 300$ and often miss the keys. May be I'll try to use CoCo3FPGA project, as I have an Altera DE2 board.

    I did manage to buy local an excellent condition very first edition of CoCo 2.

    As I understand, I can upgrade it from 16K to 64K by swapping 4116 for 4164 and soldering some wire? Are there guides with pictures?

    And there is an Extended Basic I can put in an empty socket? Is it 2764 eprom? Again, is there a guide?

    I did find this video here: https://www.youtube.com/watch?v=f6a0ZsV7OO8, so may be I'll be able to follow through.

    Can I load something from the tape like ZX Spectrum or MSX? Or is CoCo 2 disk only?

    What are my options for disk drive? I want something modern with SD card ideally.

    Please help, thank you!

    #2
    Sounds right on the ram upgrade. I've always had 64k + Extended Basic from new, I'd highly recommend it. 16k and Standard Basic is pretty limited.
    CoCo does cassette fine, uses the same DIN -> headphone, mic, remote cable as the TRS-80 model I, III, IV, and original IBM PC.
    Very much recomend the CoCoSDC for a floppy drive emulator, uses an SD card, boots straight into an easy to use menu, can hold pretty much the entire library of software for the CoCo.

    Comment


      #3
      Thank you, eswan, for your answers. Is there an active CoCo 1/2/3 community with a forum? This one seems a bit slow, I don't think it's the main CoCo hub.

      Comment


        #4
        You'll find a lot of links here at the Glenside Color Computer Club:

        https://www.glensideccc.com/cocolinks/

        Comment


          #5
          Originally posted by dhau View Post
          Thank you, eswan, for your answers. Is there an active CoCo 1/2/3 community with a forum? This one seems a bit slow, I don't think it's the main CoCo hub.
          If you're a Facebook user, this group seems pretty active

          https://www.facebook.com/groups/2359462640

          I just did something similar recently as far as upgrades to my Coco 1, https://www.facebook.com/groups/2359...9037496082641/

          Your Coco2 should actually be much easier to upgrade, but the first step would be to identify what mainboard revision you have.

          http://www.cocopedia.com/wiki/index....lor_Computer_2

          Comment


            #6
            Originally posted by dhau View Post
            Hi folks, couldn't afford a CoCo 3 as they are now over 300$ and often miss the keys. May be I'll try to use CoCo3FPGA project, as I have an Altera DE2 board.

            I did manage to buy local an excellent condition very first edition of CoCo 2.

            As I understand, I can upgrade it from 16K to 64K by swapping 4116 for 4164 and soldering some wire? Are there guides with pictures?

            And there is an Extended Basic I can put in an empty socket? Is it 2764 eprom? Again, is there a guide?

            I did find this video here: https://www.youtube.com/watch?v=f6a0ZsV7OO8, so may be I'll be able to follow through.

            Can I load something from the tape like ZX Spectrum or MSX? Or is CoCo 2 disk only?

            What are my options for disk drive? I want something modern with SD card ideally.

            Please help, thank you!
            I have listed the two Extended BASIC upgrades. It depends on your coco model
            https://www.ebay.com/itm/264912430491
            https://www.ebay.com/itm/264973699291

            To upgrade your RAM, use this:
            http://users.digitalindigo.net/techno/coco2.html

            To get programs into your CoCo... old school = tape and floppy disks
            other options
            * Drivewire - serial to modern PC RS232
            * Tape cable to your PC's audio out and in. Use Audacity to play the WAV
            * There is a high-speed tape system based on a PI
            * Gotek drive - USB stick and floppy disk controller
            * Moo Card from the UK - has SD Card
            * SDC SD Card from a few people in the states - THIS IS THE BEST OPTION

            Video Out
            Best option... CoCoVGA
            other options... various composite boards

            Think I answered all?

            I run the Color Computer Store

            Carlos Camacho

            Welcome to the community. Please google 'CoCoCrew Podcast.' Start on episode 1 and work your way through. You will learn a ton.

            Comment


              #7
              I picked one up myself recently for $185 on ebay and with some of the money I saved, I bought a 512k memory upgrade. I've seen these go north of $450 in auction format already, so the $185 BIN screamed at me to the point where I couldn't ignore it. If you persevere, you can still find deals on ebay, but it's getting harder and harder. It's not only collectors out there anymore, it's also flippers trying to price gouge the collectors. My CoCo collection now includes a white, 64k CoCo 1, a CoCo 2, and now, the CoCo 3.
              Last edited by animekenji; March 22, 2021, 03:36 AM.

              Comment


                #8
                Originally posted by hideehoo View Post
                Your Coco2 should actually be much easier to upgrade, but the first step would be to identify what mainboard revision you have.

                http://www.cocopedia.com/wiki/index....lor_Computer_2
                Thank you very much, hideehoo! I can't join Facebook, in my humble opinion the company is too immoral to help them get richer. No judgement though!​ To each it's own.

                Originally posted by ColorComputerStore View Post
                Welcome to the community. Please google 'CoCoCrew Podcast.' Start on episode 1 and work your way through. You will learn a ton.
                Hi Carlos, thank you for a detailed answer! I'm listening to the episode 0 right now.

                About Extender Basic ROM, can see the file is 8KB, so should be fine in 27C64, but you use 27C128. Is that due to availability? Also I see the adapter you're using. Is it to convert 2764 to 2364?

                What does require Extended Basic? Will some good software not work without it? Or is it mostly to run basic programs?

                I'll check out Wiredrive, sounds very interesting!

                Is mailing list still going?

                I got 26-3026 model, which is very first CoCo 2, and a very low serial number. I got it from the gentleman who used to work at a RadioShack store. I think it's using some weird +12 and -5 volt DRAM, so memory upgrade is a bit more involved. The link you provided (http://users.digitalindigo.net/techno/coco2.html) doesn't seem to have any info for this model. But I'll figure it out, hopefully.

                Where can I buy the expansion PCB for Altera-DE1 CoCo3FPGA? Or download some gerbers for PCB fabricators.

                Comment


                  #9
                  Is it possible to upgrade the memory on a CoCo 2 past 64K?

                  Comment


                    #10
                    Originally posted by animekenji View Post
                    Is it possible to upgrade the memory on a CoCo 2 past 64K?
                    Not without adding a memory-management unit (MMU), and writing software to take advantage of it. The microprocessor, the Motorola 6809, has a 16-bit address bus, which means it can only express addresses that fit within 16 bits. That's 2^16 = 65536 byes, conventionally numbered 0-65536 in unsigned decimal, a.k.a. 64KB.

                    The CoCo 3 implemented an MMU as part of its "GIME" chip to enable use of additional memory. Radio Shack sold 128KB and 512KB models of the CoCo 3, though I'm not sure you could buy a 512KB machine "stock" (I suspect you had to pay for a separate memory upgrade line-item); RAM prices spiked at the time the machine was released so such machines are relatively rare. I remember the cost of a 512KB configuration seeming prohibitive at the time. The banking technique used by the GIME supported up to 2MB of memory, and that is a popular configuration for contemporary aftermarket solutions. Back in 1986, low memory chip densities, heat dissipation challenges, and sheer expense made such a thing impractical, but times are better now.

                    It's possible there were 3rd-party MMUs for the CoCo 1 and 2 (and/or Dragon), but I don't recollect any such thing and if they exist they don't get discussed much by hobbyists these days. Little or no software would exist that could take advantage of such a memory surplus on those machines.
                    Last edited by Satyr Icon; April 15, 2021, 02:26 AM.

                    Comment


                      #11
                      How necessary is the CPU guard thing for 6809E? It is a PCB to prevent CPU from blowing up. Is it CoCo 3 specific or does it affect all CoCos?

                      Comment


                        #12
                        Originally posted by dhau View Post
                        How necessary is the CPU guard thing for 6809E? It is a PCB to prevent CPU from blowing up. Is it CoCo 3 specific or does it affect all CoCos?
                        If you're talking something like about the "Pro-Tector+" from Cloud-9, I have some guesses since no one who owns one has spoken up yet. I'll answer your questions in reverse order.

                        It's not CoCo-3-specific because the CPU pinouts are the same. And yes, the hardware modification is there to prevent damage to CPU parts, which can be hard to source, from voltage transients, I assume while bench-testing the system during other hardware work. I guess it could provide some marginal benefit to protect the CPU from bad mains power filtering (I don't know anything about the quality of any CoCo model's DC transformer) but honestly I'd have any vintage computer behind a well-trusted surge protector anyway.

                        I suppose how necessary it is depends on how often you plan to be performing the aforementioned hardware work.

                        Comment


                          #13
                          The MOOH by tormod.me looks like it might match the requirement of a MMU for the CoCo 1 and 2 and Dragon.

                          Comment


                            #14
                            Originally posted by Satyr Icon View Post
                            It's not CoCo-3-specific because the CPU pinouts are the same. And yes, the hardware modification is there to prevent damage to CPU parts, which can be hard to source, from voltage transients, I assume while bench-testing the system during other hardware work. I guess it could provide some marginal benefit to protect the CPU from bad mains power filtering (I don't know anything about the quality of any CoCo model's DC transformer) but honestly I'd have any vintage computer behind a well-trusted surge protector anyway.
                            I don’t think the “Pro-Techter” would be of any use at all protecting the CPU from voltage transients; it doesn’t have a power regulator or any filtering circuitry on it, and the 6809 is not uniquely sensitive to power problems compared to the other chips on the board. What it does do is buffer the CPU’s I/O lines so if you inadvertently (or intentionally) jolt, plug, or unplug something from the cartridge port it protects the CPU from getting shorted or possibly zapped by static charges.

                            I have to admit I’m slightly jaded about this because at the moment 6809’s are cheaper than the buffer card is, and since the buffer card has surface mount chips most casual users will have to replace the whole card if it gets zapped instead of a cheap individual chip, but... *shrug*.
                            My Retro-computing YouTube Channel (updates... eventually?): Paleozoic PCs Also: Blogspot

                            Comment


                              #15
                              Originally posted by Eudimorphodon View Post

                              I don’t think the “Pro-Techter” would be of any use at all protecting the CPU from voltage transients; it doesn’t have a power regulator or any filtering circuitry on it, and the 6809 is not uniquely sensitive to power problems compared to the other chips on the board. What it does do is buffer the CPU’s I/O lines so if you inadvertently (or intentionally) jolt, plug, or unplug something from the cartridge port it protects the CPU from getting shorted or possibly zapped by static charges.
                              Ahh, thank you for the correction.

                              Comment

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