Questions about the Memotech MTX that you were too afraid to ask...

[gunrock]

Ok, it's a click-baity title, but here's the place to ask all those questions about the MTX that have been burning (or just mildly tickling) the back of your brain for all these years!

My question: Why doesn't the MTX boot up with an introductory message?
The BBC Model B does, so too the ZX Spectrum. The Commodore 64 has its notorious 38911 BYTES FREE splash screen, the MSX has it's Microsoft branding front and centre and I believe (quick check) that the Atari 8-bits had a simple splash screen too. So why not the MTX? Not enough ROM space left? It's a shame because it's such a prime, sleek, piece of workmanship and yet the Ready prompt is just so workman-like.

Perhaps the culprit who put in "HELLO CARO" in the bloody ROM, should have saved it for a clear screen code and MEMOTECH, plus a carriage return.

[Martin A]

99% sure it is the ROM space that was the issue. If you look at the rom listing (at the botlom of Andy's pages http://www.nyangau.org/memotech/memotech.htm)

There are several chunks of code that were "commented out" to make the final code fit the available space. The FRE function, FILL in panel, and additional built in language support being the most obvious sacrifices to the space restrictions.

Oh, and the horrible error messages!

Alas finding and removing "Hello Caro" wouldn't have made a huge difference. I'd be bold and suggest those 10 bytes would have been put to better use expanding the dot off virtual screen error message!

[gunrock]

I think you are right Martin, of course. Those ten bytes would have allowed for a slightly more comprehensible error message!

Ok, another question from me: Why did Memotech pin the composite out to monochrome on quite a few MTX machines?

Evidence: I have three MTX systems, the first, a Danish machine outputs colour. The other two bought from Ebay UK from UK sellers in the last year, have their composite output set to b/w. I also saw a thread on Stardot, where 1024MAK (not stalking you, honest ) said that several machines had come into circulation and new members on the boards or facebook had reported them to be only outputting b/w, in the last couple of years.

My theory: In the 80s most people hooked their home micros up to TV's via the aerial socket. So the "Monitor out" on the MTX was for deep-pocketed individuals and institutions that had monitors. In the early to mid-80s, I'd wager most monitors were monochrome (green, b/w or perhaps amber). I suspect those display a higher quality image if you remove the chrominance from the signal.

What do you think?

[stephen_usher]

I've not come across any mono-only machines. My original MTX500, bought new in December 1984 had colour output as did the MTX512 I picked up on eBay about 5 years ago, which is seemingly an earlier machine, also had colour composite output.

Maybe those machines were modified back in the day, or a special batch for schools, set up in the same way as the BBC Micro?

[Dave]

I’d say that about half of mine were pinned mono

[gunrock]

So that's 50% of your 8^2 -1 MTX systems? A fair percentage!

Seriously though, do you do the alteration to switch them back to colour?

[Dave]

I do, but I find it easier to just snip the link on the top side (as awkward as that is), then solder a new link on the underside of the board, rather than trying to make the new link between all those other components

[gunrock]

I do, but I find it easier to just snip the link on the top side (as awkward as that is), then solder a new link on the underside of the board, rather than trying to make the new link between all those other components

That is probably what I should have done with mine, however I was a little concerned whether I might create a short against the keyboard pcb if it were too proud (the original link stands quite high and I was reusing it).

[Martin A]

I had one of each option. I did wonder if it was because the mono option gives a slightly sharper picture on a mono screen?

Jim's Red MTX had neither link fitted (see the Memofest 2017 write up) i've not heard of any others with that problem. It shows how special that red MTX is!

The back of the board link is the option I chose too. There's always A bit of insulating tape if you're concerned, but to be honest, I've only ever needed that between the main PCB and the video board not the video board and the keyboard (yet anyway).

[Potholepete]

even more so with a colour VGA output soon added to it