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Gridcase 1530 386 16Mhz Red Plasma Display Portable PC

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    Gridcase 1530 386 16Mhz Red Plasma Display Portable PC

    Someone recently gave me a Gridcase 1530 and when I powered it on there was a slight fizzle and a burnt smell from the removable power supply (it goes where the battery would go). I tracked the problem down to a shorted tantalum inside the power supply. This thing is pretty easy to work on since it is so easy to remove. I replace the tantalum with a brand new low-esr electrolytic of the same specs (closest I had on hand) and it worked! Some times when powering it on the status lights just kind of flicker and it won't turn on. If I switch it off and back on it usually works. Aside from the dead Dallas RTC which is preventing it from booting from the hard drive, it runs fine. After playing with it for an hour or so the other day (booting from a floppy), I shut it down and was working on something else. Then I heard a loud pop and smoke started rolling out of the back of the Gridcase (which was plugged in but was not turned on). I immediately suspected those old Rifa X2 caps (two 0.15uf 250v Rifa X2 caps in this case) that I'd seen inside the power supply. This is the first time I've seen these actually blow up, but I knew it was common.

    Anyway, long story short, I got some replacement modern X2 caps from DigiKey (along with ones to replace ones of different values in other systems I own, because I certainly don't want to smell that horrid stink again) and got the system running again. It still does the flickering status lights some times, but it does power on now without exploding.

    I've got it partially torn down and I'm going to try to get the board out so I can replace the RTC (why on earth didn't they socket these things???) since i have a bunch of new-old-stock Dallas chips I got cheap online (never used\initialized so they are still fresh).

    I have two questions as of right now...

    What is likely causing the flickering status LEDs some times when I try to power it on?

    And what are some games or applications that would be fun to play with on the red plasma display? I'm more familiar with CGA, EGA and VGA games, so I don't know what would be good to put this thing to use.

    Also, I will post pictures later of this adventure.

    i have a bunch of new-old-stock Dallas chips I got cheap online (never used\initialized so they are still fresh).
    No they aren't. The battery gives them a shelf life regardless if they are used or not.

    And what are some games or applications that would be fun to play with on the red plasma display? I'm more familiar with CGA, EGA and VGA games, so I don't know what would be good to put this thing to use.
    You have to treat it as a monochrome display with a color video input. Nothing really takes advantage of the screen technology so anything will work.

    My guess on the flickering is the rest of the power supplies capacitors need a refresh.
    [Need something to waste time on? Click here to visit my YouTube channel CelGenStudios]
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      Originally posted by Ozzuneoj View Post
      since i have a bunch of new-old-stock Dallas chips I got cheap online (never used\initialized so they are still fresh).
      The Dallas chips do not start draining the battery until they are used. But the battery doesn't stay fresh forever - even if it's unused... How old are they?


        Don’t remember exactly but thought the 1530 had a separate battery on the mother board just in front of the drives and behind the SIPS that powered the bios and clock. Also don’t recall if the 1520/30 would accept a date beyond 2000. The power supply pod is always on regardless of if the system is on or off, best to unplug when not in use. Or use an external power supply and feed the back power connector.
        If you have the original Grid DOS on the drive it will have things like a Gridscan program, A Grid Color Map program that allows the display to run in different modes and weird things like the Grid Mode command that controls things like the serial ports and allows the internal modem to work.
        I have found that often poor contacts between the power supply and the slot it fits in will result in the system not starting because the in rush of current for the internal power supply in the computer is higher than the connection will allow when dirty and it will cycle like that until the internal power supply can come up.
        Interesting trivia! The floppy and the IDE hard drive are regular drives and not special laptop drives.


          Thanks for the info guys! I'll be replacing the RTC today and I will try to diagnose the flickering. I'll try to be sure that it isn't a contact related issue first, then move on to caps. On the subject of capacitors, there is a secondary board toward the rear of the machine (directly behind the rear I/O ports) that looks to be power supply related. Is this still used when I'm using the removable "internal" power supply or is it related to battery charging or something else?

          As for using "old" Dallas RTCs, I got them for a fraction of the cost of brand new ones from Mouser or Digikey. The date code is from 2008 I believe. I'm just going by the information in this thread:

          So far, the ones I have used have been fine. I will say, I'd be even happier with these if I could add sockets every time, but with this Gridcase I don't know if there is even enough space to add a socket for the Dallas chip. That extra 3-4mm may prevent the keyboard from going in properly.


            Alright, I replaced the Dallas RTC, which wasn't too bad (I don't do a lot of through-hole-solder multi-leg chip replacements... mostly just capacitors and things like that).

            I decided to check out the metal spring terminals that are used when the removable power supply is inserted and I immediately noticed that all four (two are just for pressure, the other two connect to terminals on the power supply) had cracked solder joints. There is quite a bit of pressure on this if you push the power supply in, so it isn't surprising that this happened... especially when you figure that the power cable sticks out of this spot as well so if the machine was crammed against a wall for some reason it would have been directly putting pressure on the spring terminals needed to run the system. Not the best design, but its hard to blame them for an oversight like this on such an early portable system... besides, the connection still basically worked, just not reliably.

            Anyway, I applied some flux and reflowed the solder on all four of these terminals.

            Once I got the system reassembled (I hate that hinge!) I turned the machine on and it came right on with no flickering lights! Then it booted from the hard drive to MS-DOS 6.0! It also has Windows 3.1 installed but it gives a missing file error when I try to run it. Given that it is only a 20MB hard drive, I don't think Windows is really the best OS for this machine...

            I've turned the machine on and off several times and it has yet to do the flickering light thing. I really think the broken solder joints on the power terminals were causing it. The components used in this thing appear to be extremely high quality. I really like it! I just wish the video output on the back was VGA rather than CGA\EGA, because I'd probably keep this around for a neat little compact (slow) 386 system, but needing a dedicated CGA monitor to get more colors out of it kind of kills the compactness of it.

            Still, I see myself playing with this for a while. I love the plasma display. Also, the expandability of it is very cool!

            Some questions and observations:

            How is the BIOS configured? It obviously needed an RTC to boot from the hard drive, but I didn't make any changes, so I'm not sure what this actually did to make the hard drive bootable again. Also, I can't see any BIOS setup... I'm assuming it doesn't have one?

            What are the limits to the CPU, memory and hard drive capacity? I'm sure that any kind of CPU upgrade would require a clock crystal to be swapped, but I know that many systems simply aren't meant to run at anything but their original clock speed. Aside from that, I have a couple of 16Mhz 387 co-processors but I can't really think of anything I'd do on this that would make use of them. SIPP memory is extremely hard to come by, so the 1MB (4x256K sticks) will have to do for now... though there are four more slots (err... rows of holes?) to add more. The 20MB hard drive is ridiculously small for something like this in my opinion, but is definitely just a product of the year it was made. My IBM 5150 has a 20MB hard drive... even a slow, monochrome 386 system should have enough space to hold an early version of Windows and a bunch of games, but without any kind of BIOS setup I have no idea if or how I could use a larger drive.

            I will probably just keep it stock since it actually works perfectly, but if the itch to upgrade hits me, I like to know my options.


              Hi, i believe it will take up 8mb of ram but it need to be done in groups of 4 , you can only use a few specific conner drives. (but i think i have that problem solved ,i'm running 512mb cf cards in a 1530 and a 1550,just need to do a few more tests)
              there is not really any bios setup , it configures its self based on what is installed . you can run some grid setup utilities gridscan and the config ,they used to be posted on the yahoo grid group untill it closed.
              i stuck most of the files here . look in the grid15xx directory

              Good luck

              P.S Grid has its own new category down the page a bit.


                The black thing in the back is the power supply, it received the output of the battery or the power pod that stuffs in the back and would accept anywhere from 10 to 20 volts and provide a regulated 5 and 12 volt source that ran the laptop.
                Windows 3.1 did not require a lot so the 20 M drive was plenty big. The big problem is that the 1530 did not have an internal mouse or anything like that so you have to use one of the serial ports for the mouse to function. The 1550 that replaced the 1530 had an internal mouse in front of the keyboard.
                In normal use the 1530 had something like DOS shell and several DOS applications. Think the 1550 came with Windows 3.0 that’s a little different then 3.1 and wish I kept a copy of it around because it’s something you just don’t see anymore.
                Down in the grid section I have disassembly procedures for the 1530 with pictures and you may want to take a look at that.


                  Originally posted by Klyball View Post
                  Hi, i believe it will take up 8mb of ram but it need to be done in groups of 4 , you can only use a few specific conner drives. (but i think i have that problem solved ,i'm running 512mb cf cards in a 1530 and a 1550,just need to do a few more tests)
                  Oooh, I'd be really interested to know how you have got this working. I've a 1520 that I managed to patch the BIOS to support a Conner 400Mb drive but I'd ideally like to swap it out with a CF card.



                    Originally posted by Moonferret View Post
                    Oooh, I'd be really interested to know how you have got this working. I've a 1520 that I managed to patch the BIOS to support a Conner 400Mb drive but I'd ideally like to swap it out with a CF card.

                    I'll Move this to the grid section


                      Originally posted by Klyball View Post
                      I'll Move this to the grid section
                      Sorry, I didn't know that section existed, feel free to move this.