The Tandy 1000 EX was released in mid-1986 ($799) and the Tandy 1000 HX released in mid-1987 ($699) . They were Tandy's "entry-level" PC-compatible models, containing everything you need to run PC and MS-DOS software in a fully self-contained unit by means of the built-in keyboard. The Tandy 1000 SX ($1,199) was released alongside the EX and the Tandy 1000 TX ($1,199) accompanied the HX. Due to their low cost and despite their increasingly unimpressive specifications, they still sold very, very well. Lets talk about their abilities, their upgrades and their differences.
Each of these all-in-ones included a built-in 90-key Tandy keyboard with status LEDs, two Tandy joystick ports, a Tandy card edge parallel printer port, headphone output with volume control, composite video and RGB output connectors, an external floppy disk drive connector and support for up to three "PLUS" expansion cards. They have internally wired power cords and a power supply fan.
The EX and HX differ in their most obvious feature in their support for disk drives. The EX has a single 5.25" drive bay on the side and came with a 360KiB drive. The HX has two 3.5" drive bays and came with a single 720KiB drive. The HX has explicit support for three floppy drives (2 internal & 1 external) with the external drive being either a 360KiB or 720KiB drive while the EX can only support two drives (1 internal, 1 external).
CPU
The EX and HX use the same CPU, an Intel 8088 running at 7.16MHz and switchable to 4.77MHz for speed-sensitive software. They can be upgraded to an NEC V20 for improved performance relative to the 8088 but do not have sockets for math coprocessors. Due to the cramped nature of the enclosure, 286 upgrades like the 286 Express Card are simply not a practical option even if you could get them running on a bare board with a PLUS to ISA adapter.
The EX and HX have a memory limitation. They came with 256KiB on their mainboards and require a Memory PLUS Expansion Adapter board to upgrade the memory. 256KiB can run a lot of DOS games, at least off their floppy disks and the DOS that came with these systems, v2.11. The Memory PLUS Expansion Adapter also offers DMA support to the system. The SX, TX and later Tandy 1000s can be upgraded with simply adding memory chips, no exotic hardware is required.
Floppy Drives
The EX comes with a 4-pin molex connector to power a standard 5.25" drive while the HX comes with power-in-drive floppy port. You can install a 3.5" drive inside the EX but cannot install a 5.25" drive inside an HX. For installing a normal 3.5" drive in an EX, you will need a longer cable and one with a pin header rather than a card edge and a mini Molex adapter. Regular 3.5" drives, including HD drives, should be installable in the HX but you will need a way around the power-in-drive cable issue. The drive must allow you to set the drive to DS0 if you want to boot from it in the HX or to be used with the EX. You could also use a modified floppy cable that only twists pins 10-12 instead of pins 10-16 so the disk drive gets the correct signal.
Tandy sold external floppy drives for the EX and HX in both 5.25" and 3.5" varieties. They came in an external enclosure with power provided by the cable which plugged into the card edge external drive port on the back of the HX and EX. The port itself brings out standard floppy signals and there is no active circuitry in the enclosure, one could cobble together an enclosure with an appropriate cable.
Keyboard
As most of the other Tandy 1000s require the special Tandy keyboard or an XT keyboard, the built-in keyboard of the EX and HX allows you to get the computer running without having to track down one of these increasingly rare keyboards or a converter to convert a more modern keyboard to the Tandy 1000 or XT protocols. Neither the EX nor the HX has a hardware reset button, so if Ctrl + Alt + Del does not work to reset the machine, then you will have to power cycle the machine.
Monitor & Support
The Tandy 1000 EX and HX were typically sold with the Tandy CM-5 Monitor, Tandy's budget digital RGBI monitor. The CM-5 is good for games and 40-column text but does not use a particularly high resolution tube, so 80-column text will look a bit fuzzy. Tandy offered the CM-11 High Resolution monitor which, while more expensive, is much more suitable for serious work. Any digital RGBI monitor will of course work with with these Tandy 1000s. The composite video output is serviceable but 80-column text will be extremely difficult to read without turning off the color.
A CRT cannot be expected to sit on a EX or HX, the top of the enclosure is too short in width to accommodate most monitors. A monitor stand is typically used, Tandy used one with metal legs that curved backwards in the shape of a "U". The EX and HX are 3.25" in height, so a monitor stand which cam provide 4" of clearance would be good. You should obtain a monitor stand which has legs with enough space so you can access the disk drive on the side of an EX. 1980s CRTs are heavy beasts, the Tandy CM-5 weighs 28.66lbs, so make sure your monitor stand can support that weight.
PLUS Expansion boards are ISA compatible devices but use a 62-pin header right angle connector instead of a card edge. The PLUS Expansion was originally found on Tandy 1000 expansion cards and intended to compensate for the lack of expansion (three slots) found in the original 1000. For the PLUS connector, Tandy offered a serial board, a 300 baud modem, a 1200 baud modem, a Network 4 proprietary LAN interface and a DIGI-Mouse Controller/Calendar board. In Tandy's original design, the Memory PLUS Expansion was required to add in two more PLUS boards.
These systems are no fun to take apart but you will have to remove the enclosure and the shielding to get to the CPU to upgrade it. Instructions are located here for the EX, opening the HX uses essentially the same method. The HX uses sheet metal shielding but the EX uses plastic sheets wrapped in aluminum. This stuff in the EX is rather nasty and traps in heat, so I would suggest removing the top pieces of the shielding for good to extend the lifespan of your system. Fortunately the CPUs in all the older Tandys are socketed for easy upgrading. The EX's shielding is sufficiently flimsy that you can cut holes in it for the CPU and Smartwatch upgrades with an X-Acto knife.
Tandy offered a Smartwatch Real Time Clock upgrade, but for its all-in-ones it only officially said it was compatible with the HX, not the EX. This Smartwatch upgrade consisted of a Dallas DS1216E, which is a chip that fits underneath the BIOS chip of a PC. The upgrade was not officially supported on the EX. I suspect that this was the case because the EX has two mainboard revisions. The upgrade works without issue on the mainboard where the BIOS chip is below the PLUS connector but will not work with a PLUS card on the revision where the BIOS is next to the PLUS connector. The extra height added by the DS1216E will keep the PLUS card from being properly seated. Like all PC systems without a built-in RTC, a driver must be loaded in AUTOEXEC.BAT to load the date and time stored in the RTC to DOS.
There are more modern solutions available than using a vintage Smartwatch chip, which has probably a dead battery by now. Note the need for a Y2K-compliant driver as stated on that page. This upgrade can work with either EX mainboard revision.
EX and HX vs. SX
The EX and HX are based off the SX mainboard design and have advantages and disadvantages relative to the SX. Their most obvious advantage is that they use a headphone with a volume wheel. This allows you not only to adjust the volume of the internal speaker but also to be able to listen to the computer via headphones without disturbing anyone nearby. Access to the SX's speaker volume control requires opening the system. Due to the way the audio multiplexer works in the EX and HX, you will always hear Tandy 4-voice PSG audio. In the original 1000 and SX some games would not set the audio multiplexer correctly and you would need to run a game that does or use a program to set the multiplexer correctly.
The presence of DMA can be both a benefit and a drawback. If there is no DMA controller in the system then the CPU will handle the transfers to and from memory and the disk drive directly. Most of the time you won't notice its presence or absence because programs do not process input while the disk drive is being accessed. But there are a few self-booting games in their original disk form require DMA or their copy protection schemes will fail. Most Formaster Copylock and very early Sierra On-line protected titles require DMA. Known games and versions include:
Crossfire (PC)
Crossfire (PCjr rev1)
Frogger
GATO (v1.4)
The Great Escape (Thunder Mountain)
Hardball (Accolade) [5.25 rev0] (EGA Disk)
Hardball (Accolade) [5.25 rev1] (EGA Disk)
Hardball (Tandy Corp.)
King's Quest (128k Sierra PC rev0)
King's Quest (128k Sierra PC rev1)
Mr. Cool (rev0)
Quink (Thunder Mountain)
Top Gun (Thunder Mountain rev0)
Ultima II (Sierra PC rev0)
Ultima II (Sierra PCjr)
Ultima III (rev0)
Ultima III (rev1)
Ulysses and the Golden Fleece
One game, The Demon's Forge (Mastertronic Release), will only show 16-color Tandy 320x200 graphics if DMA is absent in a Tandy 1000. The DMA in the SX, TX and later computers cannot be disabled but the DMA can be removed from the EX and HX.
System Configuration
The EX does not present much in the way of configuration beyond what you add to the system in the form of PLUS cards, memory, CPU and clock upgrades. It uses the same BIOS as an SX. Both the EX and HX have only a single jumper. The jumper is used to connect the Select Printer (Status Port) signal to the printer port. The printer port is capable of running an OPL3LPT with a Tandy card edge to DB-25 adapter.
The HX brings a few features to the table compared to the EX. The HX has a boot menu that by default shows up when you boot the system. From its DOS disk it can access a setup menu with the SETUPHX program. The setup menu saves its settings are stored in an EEPROM chip. Its settings are all stored on one text page, it does not have a /a command line option to bring up additional pages of advanced settings. The HX comes with DOS-in-ROM. But before you write the EX off, not all of those features have significant value today.
The biggest advantage of the HX over the EX is its instant boot feature. This bypasses the memory check but shaves about 14 seconds off a boot. The lack of a memory check on every boot may make it more difficult to diagnose issues if the computer is acting strangely. You can turn on the memory check in the setup menu. If you're booting to DOS you can save several seconds because DOS does not have to boot from a floppy disk.
The HX startup menu may have been convenient back in the 1980s for new computer users but has little utility today. The "startup from internal drive" option is intended for self-booting programs or a full MS-DOS boot but it can cause issues with programs that expect to be the first and only program run on the system. If you add another floppy drive the HX will not detect it until you run the setup program. The setup program will show "View Programs on Drive B:" and "Startup from External Drive" on the menu afterward. You disable the menu by selecting MS-DOS as the initial start-up program in the setup program.
The EX supports the F1-F4 key configuration options for monochrome mode, TV mode, swap drives and fast/slow speed. The HX does not, you must set these in the setup menu and they remain set until you change them again. Alternatively the Tandy MS-DOS MODE command can set the system into monochrome mode, TV mode and set the CPU to slow. This only works until your next boot, whether by a power cycle or by a Ctrl + Alt + Del. If you want to use self-booting programs with the slow mode, you must set it in the setup menu. If you wish to boot the external drive on the EX, you will have to press the F3 key while the memory check is running. You can set the HX to always boot to the external drive or use the startup menu to boot from the external drive. While an EEPROM is a robust device, it does have a limit to the number of times (at least 10,000x) it can be written to, so you shouldn't change settings too often.
The DOS settings in the setup menu, such as disk buffers, open files and MS-DOS country code only apply when running DOS-in-ROM.
Deskmate
The EX comes with Personal Deskmate and the HX (and the TX) with Personal Deskmate II. Personal Deskmate came on two 5.25" disks while Personal Deskmate II requires only a single 3.5" disk. These are the first versions of Deskmate with a GUI and one of the earliest GUIs available for the IBM PC platform. These versions of Deskmate require Tandy video and only run on systems which support Tandy video. Either system can run either version of Personal Deskmate.
Personal Deskmate will only show the mouse cursor correctly using either the Digi-Mouse driver or the Tandy Joystick-Mouse driver. Personal Deskmate II changed the color scheme, added a music program for 3-voice music using the Tandy sound chip and added new options to the Paint program such as full-screen 16 color support. Its mouse cursor will display correctly using most mouse drivers. The HX can be set to boot automatically into Personal Deskmate I or II if that program's disk is in the drive. I originally used to think that a portion of Deskmate was in the HX's ROM, but that is the case for the SL, TL and later Tandy 1000s.
MS-DOS
The version of MS-DOS which came with the EX is v2.11.24 and the HX had v2.11.26. Both only require one disk, 5.25" for the EX and 3.5" for the HX. The HX's version of MS-DOS is notable because it supports 3.5" disks with their standard 720KiB capacity. Usually only versions of MS-DOS 3.2 or higher support 3.5" disks at their full capacity but Tandy was able to get the support into a less-advanced version of MS-DOS. MS-DOS v2.x is limited to a single hard drive of 15MiB or less, so if you use a hard drive you need a more advanced version of MS-DOS. If you use a later MS-DOS take the version of MODE.COM from one of these disks so you can access the special Tandy functions like slow mode in DOS.
DOS-in-ROM has a definite advantage if you are running MS-DOS based floppy software and do not have a hard drive. On the EX as it shipped with the single disk drive, to run MS-DOS software you first had to boot your DOS disk and then swap to your program disk. Some programs had the ability to make themselves bootable, but that could be dependent on the DOS version as some DOS versions were too big to fit in the space the program set aside for the system files. On the HX you can boot to enough of a DOS built into the mainboard to get programs running. The setup menu allows you to change the number of open files and buffers available to DOS programs, something that is ordinarily specified in a config.sys file.
International HX
The HX has some international support built in and it was sold in Europe and Australia, but in very limited numbers. Tandy computers were not very popular outside of the US and Canada and an "International Tandy 1000 HX" is a very rare beast indeed. Domestic U.S./ and Canada EXs and HXs come with power supplies that only handle 120v input, so if you're importing one and you're living in a 240v country, you will need a step-down transformer. The available options for these system are not likely to stress its 28w power supply that much, so you may experiment with running the system with the fan disconnected. The fan is soldered onto the power supply board and the power cable is connected internally. A photo of the keyboard of a French HX is here.
The XT-IDE adapter and memory expansion makes DOS-in-ROM redundant because the DOS on the "hard disk" will need to boot to allow access to the storage of that hard disk. A CF card boots DOS very quickly, so you can access DOS floppy disks without losing the benefit DOS-in-ROM. In the setup program for the HX, you will need to make sure that the primary boot device is set to "Disk", not "Memory".
A Gotek floppy drive emulator with FlashFloppy or HxC firmware is an excellent upgrade for these systems. However you should be aware that the EX puts the drive out on the side, so you will have to move your body or the system to see the display on the Gotek drive. A small mirror angled correctly might do the trick.
I had friends with these. We trucked along with our 1000A from Christmas of 1985 until I left for college in 1992. That puppy was bypassed like a Christmas tree. I doubt Scotty could have upgraded it more!
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