Lobsters retrocomputing - 13 Sep 2026

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Inside the box is a demonstration tape, a heavy unregulated wallwart that would likely dent your skull if lobbed incautiously (outputs a nominal 8V DC 1.5A centre positive), an RCA cable for connection to a TV set (but no switchbox) or monitor, the user manual, a BASIC "application programs" book with simple sample BASIC programs for type-in, and a larger spiral-bound BASIC reference manual. Under the manuals is a 1/8" audio cable for the cassette port terminating in input (black) and output (red) leads.

I was immediately suspicious of the wallwart and bought a regulated 9VDC 2A switched wallwart to replace it (the machine will run fine at this voltage). The user manual proper is very sparse, mostly just how to hook the computer up. The BASIC "reference manual" picks up from there, less an encyclopaedic reference text than an in-depth tutorial.

The rear ports consist of, from left/west to right/east in this view, power jack, cassette jack, RCA jack for composite video, the expansion port, the peripheral port, and finally RF output for a TV set. There are no slots on the sides, only a single rocker power switch. The main difference between the expansion and peripheral ports is that the expansion port gets the full 16-bit address bus and certain other processor lines, while the peripheral port (also referred to as the I/O port) only sees the lowest eight bits of the address bus - all that would be required for using the Z80's 256 I/O ports - and a smaller set of control lines.

Notice the peripheral slot still has its cover on it, secured by two small screws, which ordinarily would have been removed before use. This is where the joysticks and printer interface (again, I have found no evidence it was ever sold States-side) would have connected, and we'll see why it was never used shortly. There should be a cover for the expansion slot also, but it was removed, because the 16K RAM expander connects there. The cover is not in the box and I'll presume it was lost or destroyed by the previous owner. That's annoying from a preservation perspective, but no great loss functionally, because we'll have something plugged in there pretty much all the time later on.

The underside of the unit is also noteworthy (serial# V078451). For this discussion I invite comparison with Bill Loguidice's computer (serial# V024662), which he has since sold but pictures are still on the Wayback Machine, and is the only other NTSC VZ200 unit I have seen myself. Both his and mine have a "VZ200 Color Computer" bottom plate with a copyright date of 1982, and both have US FCC clearance tags and an RF switch to pick the channel (2 or 3). There are passive cooling vents on both sides, though given the fairly small amount of clearance its rubber feetsies afford from one's desk I hesitate to say they'd be effective. (At least they let you hear the piezo speaker.) There is also a small red sticker on the bottom which on mine is partially missing, but Bill's has a complete one, which reads "U NTSC 4K." I put a small piece of transparent tape over the sticker on mine to prevent further damage. Bill's unit also has both port covers.

Although the serial number indicates his is a rather older unit, which we'll in fact confirm later, the label and keyboard are the same as mine and not those earliest CES models. Both units have FCC Part 15 clearance, specifically as a Class B computing device for home use; at the time Class B regulations were very strict and we'll see a consequence of that inside. The FCC ID is BNX84H80-0323, with an equipment authorization (EA) applied for February 10, 1983 and granted May 9, 1983. Accounting for publishing delays, this means Creative Computing must have had a pre-authorization prototype for their review. VTech later applied for a revised equipment authorization on July 11, 1983 and was granted BNX84H80-0323-1 on October 11, 1983; this change may have been for redesignation as the Laser 200. The listed address for VTech in Hong Kong appears on all entries for FCC grantee BNX and doesn't seem to have been their corporate address at the time, but the tester in both EAs is one Thomas Cokenias from Electro Service Corp., at 1116 Ninth Avenue in San Mateo, California, and Cokenias and Electro Service are seen in other EAs around that time for other Hong Kong manufacturers. However, the given address appears presently unoccupied, and the California Secretary of State indicates Electro Service is no longer in business.

The other two boxes contain the RAM expander and the JS-20 joysticks/JI-20 joystick interface. Now we see why the peripheral port cover was still on: these joysticks are unused, still in their original bag and packaging. (Note from the future: as we'll see, many games play just fine on the keyboard, so the prior owner may never have needed them.) Though the joystick interface comes with a small instruction pamphlet, the RAM expander does not. Bill did not have either of these devices and that's likely why neither port on his machine was ever used. Let's get out the rest of the family. VTech continued the evolution of the Laser 200 series with the Laser 310, a cost-reduced upwardly compatible version that used several gate array chips instead of discrete logic, but added more RAM (16K plus the 2K video RAM) and, for the first time, a proper keyboard with real keycaps and even a space bar. This time there would be no NTSC version; the 310 was never even announced in North America, instead launching in April 1984 at CeBIT in West Germany. It was sold in at least that country as well as France and mainland China, and Dick Smith picked it up for 1985 as the A$199 VZ-300. VTech had also developed a disk drive upgrade for the series, which DSE eagerly sold, and virtually all of the VZ-300 peripherals except its 16K RAM expansion (due to differing address mapping) would work on the older machine because many of them were effectively unchanged except for the labeling. (The address mapping difference is also why the VZ-200 16K RAM expander will work on the VZ-300, but only giving you an additional 8K.) Although there have been various other members spotted in the Laser 300 series, apparently differing only in RAM size or case type, none were reportedly sold widely if at all.

The VZ-300/Laser 310 is otherwise nearly totally compatible with the VZ-200/Laser 210 except for its clock speed. As NTSC compatibility was no longer required, VTech switched to a single 17.734475MHz master crystal divided by four for the 4.43361875MHz PAL colourburst and five for the 3.546895MHz CPU clock. (The Motorola 6847 VDG in the VZ-300 and PAL systems generally is clocked with an altered signal which I'll talk about when we open the machines up.) Although that makes the VZ-300 slightly slower at 99.09% the speed of the VZ-200's 3.5795454MHz (315/88) oscillator, in practical terms the difference was imperceptible with most existing software - but of course it's going to be a problem for us later. VTech did no other upgrades, not even offering an alternate 6847 font ROM with lowercase, though we'll talk more about that when we get to the innards as well.

The DSE VZ-300 and VZ-200 have prominent Dick Smith branding and are both labeled as "Personal Colour Computers." The keyboard layout of the VZ-300 is almost identical to the VZ-200 except for a second SHIFT key where the SPACE key used to be and then an actual SPACE bar below that. The keys are wired the same for compatibility, however, so the two VZ-300 SHIFT keys look like the VZ-200's single SHIFT key, and the left/right/up/down cursor block on M, comma, period and SPACE is necessarily broken up on the VZ-300 because of the SPACE key moving below to the larger SPACE bar. Early VZ-300s had brown keycaps with varying labeling, but later units like this one from about 1987 on have platinum-coloured keycaps that match the case. The effect is (probably intentionally) reminiscent of the Commodore 64C, just shorter. I don't have all the accessories with my VZ-200 that I do with my VZ200, nor do I have its original Dick Smith retail box, but for the ones I do have I've compared them together in this photograph: the two main computers, their demonstration cassette tapes, and various documentation. The VZ200 BASIC Reference Manual and the Dick Smith Basic [sic] Reference Manual both appear to be identical down to the use of American spelling, even in the Aussie version, which calls into question the claim in Hartnell's review that it was written by VTech "under strict instructions by Jime Rowe [Jamieson Rowe] of Dick Smith Electronics" even though it is also not unreasonable to believe that DSE had some role in shaping it.

On the other hand, one manual unique to the VZ-200 was the Technical Reference Manual (TRM), which Rowe, by then highly placed in the Dick Smith organisation, wrote himself from VTech internal documents. This slim A4 book was never sold in America, and was a Christmas gift from my wife (I married well). The DSE pricetag on the back gives its price as A$9.50 but I don't know where or when it was originally purchased. While the TRM does not approach the sheer detail of, say, the Commodore 64 Programmer's Reference Guide, which even has an exhaustive memory map covering its 64K of RAM and 20K of ROM, it does include documentation on most of its important RAM locations and a full set of schematics, some of which we'll be using in this very article. A similar manual exists for the VZ-300 with its own set of schematics, which also discusses the VZ-200 and has some details not in the earlier text.

My VZ-300 system has more of the peripherals but little documentation. Displayed here clockwise from the lower left/southwest corner is a VZ-ASTEROIDS tape sold by DSE that would work on a VZ-200 with RAM expansion also, the VZ-300 Centronics printer interface (also works on a VZ-200), VZ-300 16K RAM expansion module, its own set of JS-20 joysticks and JI-20 interface (identical, differing only in badging), and its demonstration cassette. On the underside my Aussie VZ-200 (serial# V027967) has a custom Dick Smith plate copyright 1983 and some quality control stickers, but no FCC badge. Although the aperture for the channel switch is still present, it has no actual switch. On the other hand, for the VZ-300 (serial# V224844) the switch was repurposed for black-and-white or colour output, which disables or enables the colour encoder circuit as appropriate. Interestingly the VZ-300's plate does not mention Dick Smith at all, nor have a Dick Smith part number or even a copyright.

A single teal sticker on the VZ-300 says "PAL-V 18K." This likely means VHF because the DSE VZ-300 sends its TV signal on Australian channel 1 (57.25MHz), and the VZ-300 schematics show separate circuits for PAL-V and PAL-U, which accordingly would be UHF.

Although the ports are the same too, when I got my VZ-300 it had already lost both its port covers. The demo tape appears to be exactly the same between all three systems. While my DSE VZ-200 tape is missing its label insert, here is the one for my American VZ200 ... ... and on the right, for the VZ-300. You'll note they are almost exactly identical, including the idiosyncratic "Have Fun [sic] with your demonstration programs!!!" step 11, and also use American spelling; the only differences are the part number in the lower left, and the absence of a copyright message on the VZ-300 insert (replaced with "MADE IN HONG KONG"). On the left is the insert for the Asteroids tape, though it seems to only have generic loading instructions. At the time DSE Pty Ltd was on the corner of Lane Cove Road and Waterloo Road in North Ryde, New South Wales (today postcode 2113 is Macquarie Park). This location housed a retail store and their main warehouse, which remained in operation until around 2001 when the warehouse was moved to Chullora (for Los Angeles residents, read "Vernon"). The North Ryde building was subsequently occupied by German truck and bus manufacturer MAN, whose old stripped logo can still be seen on the facade, and is now split between multiple tenants. This is how my PAL VZ-200 comes out on my trusty NTSC Commodore 1702 monitor, the best JVC CRT screen Commodore ever rebadged. The picture rolls a bit and there is of course no colour (because it's being encoded for PAL) but it's enough to show you the ROM version, which is 2.0. These were the last ROMs used in the Laser family and are the same ROMs in the VZ-300 as well. This setup also serves as a weak mockup of what an American black-and-white VZ system might have looked like - everything could otherwise be the same modulo the absence of a colour signal. The character glyphs come from the default Motorola 6847 font ROM built in to the video chip.

Early Laser 100 computers came with 8K of ROM containing TRS-80 Level I BASIC, while the prototype VZ200 units shown at CES had an larger 12K ROM set apparently using upgraded TRS-80 Level II BASIC. Subsequent Laser 200/300-derived systems and the Laser 110 have 16K of ROM and TRS-80 Level II BASIC as well, which was deliberately obscured in later revisions of the ROM. Level I BASIC is quite, uh, basic, evolved by TRS-80 designer Steve Leininger from Li-Chen Wang's "copyleft" Palo Alto Tiny BASIC which Leininger substantially altered, reworking its structure and adding floating point math (because it couldn't accept Charles Tandy's salary when he typed it in), two string variables and a single array, and support for the TRS-80 hardware. VTech's version is similarly modified to support its own architecture but is otherwise the same. Level II BASIC is Microsoft BASIC, derived from Microsoft's own Extended BASIC on the Altair, and again VTech initially imported it nearly unchanged except for adding support for their hardware and graphics, which replaced some of the keywords (like TROFF with COLOR). Proof can be seen by comparing the order of keywords in their token tables, which would have no reason to match as precisely as they do unless they came from the same origin. Another persistent relic in the VZ BASIC ROM is the old Microsoft two-character error message table (e.g., ?SN ERROR instead of ?SYNTAX ERROR) even though the existing code never references it.

Tandy's apparently successful legal action against EACA and PMC spooked VTech that they could be sued in the same way - but by Tandy and Microsoft. The company's solution was to dump Level I BASIC entirely, eliminating any objection from Tandy, and for Level II BASIC to secretly null out a large number of entries in the ROM BASIC keyword table potentially unusual enough to be used as evidence of copying. The tokens for those keywords still remained valid, however, and the ROM code for them also largely persisted. Disk-specific keywords were likewise omitted in the same fashion, at least until the VZ-300 disk drive debuted, but unlike the other gutted keywords were instead vectored through RAM for later expansion. These keywords (in token order) are CMD, RANDOM, DEFINT, DEFSNG, DEFDBL, RESUME, ON, OPEN, FIELD, GET, PUT, CLOSE, LOAD, NAME, KILL, LSET, RSET, SAVE, SYSTEM, DEF, DELETE, AUTO, FN, VARPTR, ERL, ERR, STRING$, INSTR, TIME$, MEM, FRE, POS, CVI, CVS, CVD, EOF, LOC, LOF, MKI$, MKS$, MKD$, CINT, CSNG, CDBL and FIX. Because their implementations often remained present, it was possible to resurrect many of them by hooking into the RAM vector for tokenizing "new" BASIC keywords, and some BASIC extensions did just that.

The earliest versions of the Laser/VZ ROM use light green text on a dark green background. Without a colour encoder this would produce light text on a dark screen, which is indeed what you see on a black-and-white Laser 110. Bill's earlier NTSC VZ200 is the same way, using the same ROM 1.2. By ROM 2.0, as in this VZ-200, the display became dark green text on a light green background, like the Tandy Color Computer which uses the same MC6847 video chip.

My unit here is also ROM 2.0 and comes up the same way, now with proper NTSC colours. This is notable because that means the American VZ200 must have remained in production long enough to actually get these final ROMs. Since we know that it's at least able to power up, we'll switch over to the composite capture rig for the remainder of our screenshots. The presence of the 2.0 ROMs raises the question of whether we really have a 4K or 8K system here, despite what the sticker on the bottom says, so we should check that first. The VZ200 memory map is detailed in the Technical Reference Manual, but in broad strokes places ROM from $0000 to $3fff, option/cartridge ROM (or nothing) from $4000 to $67ff, memory-mapped I/O from $6800 to $6fff, video memory from $7000 to $77ff, and then the rest of RAM from $7800 to whatever the "top of memory" (TOM) is, either $ffff or the end of physical RAM, whichever is less. (This layout is not exactly as described if the disk system is present, but we're going to ignore that for our current purpose.)

On startup the ROM tests available memory and stores that final valid RAM address to the systemwide TOM pointer at 30897-8. On a 4K system we would only have 2K of general RAM available, so the TOM pointer should be at $7800 + $07ff, yielding $7fff or 32767. That is indeed the value of the TOM pointer, so we do have a 4K system, just a very late one.

You may have noticed the oddly convoluted BASIC statement I entered to get that figure. That's because I had to avoid typing the number 5: the key didn't work. Normally the VZ200 will beep as you press keys, but there was no beep and no response when I did. In fact, an entire run of keys (5, T, G, B and N) was not working, and I was only able to enter the PRINT keyword by pressing SHIFT-P. We'll need to fix the keyboard now to do anything substantial with this machine.

In the TRM's schematics we find the keyboard matrix, which is divided into an 6x8 grid with rows selected by the lowest eight bits of the address bus. (The TRM explains in section 3 that the matrix is scanned through simple memory-mapped I/O, another common attribute of crap home computers, even ones with CPUs like the Z80 and TMS9995 that have perfectly cromulent and proper I/O space.) The six columns are normally pulled high to +5V by a block of six pull-up resistors. As each address line row is cycled low during keyscan, if a key is pressed in that row, it will register a corresponding low level in its column to the chip at U12 which emits the six-bit result for the effective address onto the data bus.

My initial theory was that the column connected to R8 and U12 pin 8 was bad, which involves our 5, T, G, B and N keys as predicted. However, this column also involves the 6, Y and H keys, which did appear to work. Still, it seemed like the most reasonable place to start, so let's crack the computer open.

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Original: http://oldvcr.blogspot.com/2026/09/a-dick-smith-vz200-without-dick-smith.html