MTX Repairs and testing

[1024MAK]

Should have posted this earlier

Since writing about using Andy Key's memory board, I have received a REMEMOrizer from him (thanks again Andy).
After studying the documentation on his site, I realised that I could just remove the memory board and fit the REMEMOrizer.

Powered up and found it worked fine.

Here is a an extract of the email that I sent to Andy

Hi Andy

Got the REMEMOrizer working!

Did scratch my head at first, because I was fitting it to a MTX512 (a real one with 64kbit DRAM chips), but the set-up only talks about MTX500's and MTX512s2.
Further complicated by me disabling all the main board DRAM (because it has a DRAM fault).

But after re-reading the instructions three times (and actually reading all the set up section), I got my head around it.

So plugged the REMEMOrizer in (my, it's a tight fit on the edge connector, much tighter than the Spectrum, ZX81 and Acorn edge connectors).
Connected a VGA display, and powered up. Waited for the LED's to change state, pressed reset and... no picture.

The display I normally use with 8 bit computers is actually a Sharp Aquos LCD TV which has RGB SCART, composite video and VGA inputs (amongst others).
But on the VGA input, all I got was an out of range information box

So I switched the TV back to composite video, only to see another blank display. Okay, a few seconds passed before I remembered that in CP/M mode the TMS9929 VDP 40 character display does not show anything.

So I robbed a true LCD VGA monitor and lead from a PC, plugged it in, connected to the REMEMOrizer, switched on, reset the MTX and hey-presto, I got the CP/M start-up screen.

So I tried a few things. Then I attempted to load a game. CP/M accepted the command, then the screen froze. What's up now?
Another few seconds passed, and then I remembered - the game is running on the TMS9929 VDP display and I had left the Sharp Aquos TV switched off - doh!

So tried playing some of the games and as per normal, I did not last long. I should have plugged a joystick in, but using the keyboard, I played enough to prove that everything is fine

Thanks for a really good bit of kit.

Mark

I should add that as I had disabled the MTX on board DRAM, and it is a 64k DRAM machine, I did not change the existing PAL chip. This may be different for your MTX.

Mark