*** M E M O R U M ***

That looks terrific. With minor modification at the rear it would work with the CFX as well.

Given that the schematics and GAL code are freely available, recreating the original is probably the simplest method.

Or get the Pi to pretend to be the MTX keyboard to the MTX and use the original keyboard for its own input, with possible pass-through.
(I know that the way the MTX scans the keyboard is a nightmare to simulate.)

If you've got a multimeter which can measure current, pull the fuse and clip the multimeter between the two sockets and see how much the machine is drawing. It should be pulling about 0.85 amps. Anything significantly more than that and something is taking too much.

Thank-you for the explanation etc. My goodness it's complicated. I'm surprised that the MTX500 and MTX512 save files are different and address dependent. (I also can't remember trying to write a lunar lander program!) As for the drop-outs, I think we can blame rubbish WHSmith C15 cassettes as I have...

I was wondering what the parameters did. Is there any documentation?

Of course, once I've the MTX files I'll have to somehow get them on the CFX CF card

Getting to know this utility would help later getting my other tapes read.

H-L Slope does the best job, but it doesn't seem to do a good job.

You can find the two wav files (recorded from my hifi tape deck with Dolby turned off) here: http://www.lingula.org.uk/~steve/share/memotech/

I got a better copy using a different tape recorder, it still doesn't work, probably due to drop outs.

I'll upload the wav files to my web server and write a new posting when they're ready.

If it were the VDP I'd not expect it to work at all.

Seeing as it works until warming up I'd get a freeze spray and see what part of the system works when cool.

I must admit that it doesn't look right from memory when I was testing my machine.

If it's the crystal then at least it's something cheap and relatively easily replaced.