Digital Symphony Installer

I’ve only got scans of the copper side, not the ident side, here – of the main board and the tube base. Not sure whether they’re a matching pair, either. Downloadable from this security-by-obscurity location:

http://clive.semmens.org.uk/2_MV4PP/PCB250.jpg

http://clive.semmens.org.uk/2_MV4PP/PCB253.jpg

I’ve emailed Crispin to dig out whatever I’ve got in the filing cabinet at the old house.

Why are the tracks all wobbly rather than point to point? Is there an electrical reason for this?

That bigger board is a work of art. You can see snakes, tadpoles, seahorses, chulthu, and various other bits of mythology…

Is there an electrical reason for this?

Yup. Minimizing intertrack capacitance, and in some places, ensuring that clearances are sufficient for the voltages between conductors. CRTs have some pretty hairy voltages…and there are legal requirements around the mains conductors.

A lot of those old components are pretty chunky; there are relatively high currents and voltages even away from the UHT components – and they have a horrible tendency to interfere with the relatively tiny signals coming in.

It’s a single sided board, too, so it’s a maze – it used to be a matter of pride to minimize the number of copper links on the component side, so tracks wiggle around to avoid crossing over each other.

The little mouse was my trademark – it started out just as two small pads for ears on a larger pad for the face – there’s one of those in the copper and one in the resist on the big board – and gradually developed. Whiskers on that tube base.

I’ll put up another one I did for a different client in a minute, where the mouse is smoking a pipe…

http://clive.semmens.org.uk/2_MV4PP/PCB251.jpg

http://clive.semmens.org.uk/2_MV4PP/PCB252.jpg

(No wire links on the component side of that at all.)

Thanks for the explanation.

CRTs have some pretty hairy voltages

Oh, yes. If those numbers on the board are voltages for testing… 😱

I made the mistake, as a child, at boarding school, of helping to “repair” a large TV. Think a CRT something like 30 inches, in a wooden box with a cardboard back and a ton of dust inside. The dining room television.

It stopped working one Saturday, so a bunch of us took it down, opened it up, and identified that by hitting it we could get it to almost work, so we went to look for anything inside that might be loose.

I decided that it would be helpful to move that big thick annoying cable out of the way. It popped out of the side of the CRT and…

…I have no memory but I was told that I basically backflipped clear over a table and destroyed the one I landed on.

Matron nearly had a heart attack. I think my friends wet themselves laughing. And it hurt all over for ages.

There’s one thing I’m loathe to go anywhere near, and that’s the inside of a CRT.

and they have a horrible tendency to interfere with the relatively tiny signals coming in.

Yeah, I looked at a schematic of my oscilloscope ¹ and was thinking that it’s pretty amazing that a millivolt sized signal could make it through all of that.

¹ https://elektrotanya.com/metrix_ox-710_sch.pdf/download.html (has a captcha, and takes about 30 seconds to “prepare” the download)

The little mouse was my trademark

Cue Disney lawyers in five, four, three……

Different domain – did the Apple record company sue Apple computers? No, they couldn’t.

did the Apple record company sue Apple computers? No, they couldn’t.

Erm…
Apple Corps v. Apple Computer

I was thinking more “trademark”.

Apple, the company, with a distinctive silhouette of an apple that has a bite taken out of it…

…is opposing the trademark application of a company called Prepear because they seem to think that people might confuse an outline of a green pear (with a leaf) with a silhouette of an apple (with a bite missing).

The case is clearly bollocks to anybody with a brain, and I rather hope Apple loses this one because if they don’t then it means it’s basically open season on any logo that vaguely resembles a roundish fruit (and it doesn’t matter if it’s a different domain, if the overpaid lawyers think it looks similar……).

Yeah, if it looks like an apple then maybe. But it’s a different shape, an outline not solid, and a different colour. The only thing it really has in common is that it’s a fruit.

The case is clearly bollocks to anybody with a brain,

Which Apple clearly don’t have enough collective braincells to form. Either that or they forgot things like the failed actions against Apricot and similar companies.

Back to the Disney case – the main reasons I’m safe are:

1) I’m a man of straw – no appreciable assets;

2) I’ve not actually caused them any damage, and very few people ever get to see my “trademark,”

3) I’m not “paasing off” my stuff as Disney’s, nor making any money out of the mark.

Oh, and I’ve not used it for nearly forty years…

Erm… Apple Corps v. Apple Computer

Interesting. I’d forgotten that Apple (Computer) have entered the Music business. Given that, perhaps the cases did have some merit. And Apple Corps have made a fairly tidy sum out of it over the years, even if they did lose the most recent round.

Sadly, my “trademark” isn’t a registered trademark, so even if Disney do make a surprising move into selling PCB designs, I’m in no position to sue…

Clive is safe. It does not infringe on IP rights.

I’ve now got pictures from son of more Microvitec info:

http://clive.semmens.org.uk/2_MV4PP/CableTVCircuit.jpg
http://clive.semmens.org.uk/2_MV4PP/TB2_Ident.jpg
http://clive.semmens.org.uk/2_MV4PP/LCCD02_Circuit.jpg
http://clive.semmens.org.uk/2_MV4PP/InterfaceIdent.jpg
http://clive.semmens.org.uk/2_MV4PP/Interface_Tracks.jpg
http://clive.semmens.org.uk/2_MV4PP/LCCD02_SolderSide.jpg
http://clive.semmens.org.uk/2_MV4PP/LCCD_Ident.jpg

Note that the previous picture was of version 3 of the Microvitec monitor’s motherboard; these pics are all of version 2.

The Interface pictures might be useful if you actually have one, but I don’t have a circuit diagram for it. Not sure, but it might well be the interface that matches A3000 signals to the Cub. I think the BBC Model B matched straight to the main board.

The cable TV circuit was for a different client. The tiny circuit board I posted the link to before is the video pre-amp in the dotted rectangle at top right – it’s designed to go in an aluminium box – a Faraday cage – to protect it from interference from the more powerful parts of the circuit. You could probably source the transistors for it – but I’d be very surprised if you could source the big IC for the main circuit, forty years on.

(All these images, although I did them all, really belong to Microvitec, or that other nameless client; but I’m pretty certain that almost forty years later nobody cares. Four channel cable TV?? Not sure, perhaps you could actually work out who the client was…)

I’m relieved to hear you’re so positive about 32-bitting it, as I realised I had told Gil that JASPP would want the sources – without actually consulting with you in advance.

I’m sure they offered to send me the source years ago, but to date I’ve not received it.

thanks for all the great work you’ve done on preserving so many Acorn 32-bit games and utilities. It really is fantastic.

Thanks, I appreciate the compliment.

I remember back in the day removing the copy protection of Symphony. I had a legally purchased copy (and still have) but I think I upgraded my machine and it no longer worked. Don’t think it took me long to do if I recall either. However with that being said I have not used Risc OS for a very long time, I do have a back-up of my Iyonix which I intend to put on a memoy card to use in my newly aquired Pi 400 and its highly likely that Digital Symphony is on that backup.

I hope someone finds it, i remember lusting after it back in the late 90s.