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BrianF wrote: ↑01 Apr 2025 22:00
Thank you (and Mark) - this is the piece of the puzzle I was missing! I'm feeling a little more positive about the condition of the machine now.

Yes, the same answer as I pointed you to originally !

Thank you for the very quick response. I assume that you are referring to one or more of the 4116 chips failing, which is also a common curse on the Spectrum. As mentioned, I'm completely new to the MTX, so I'm therefore intrigued to understand why a VRAM issue might also cause basic BASIC commands...

gunrock wrote: ↑30 Mar 2025 21:21 Four minutes to reply - gotta be a record, yes?

Or are you just sitting there Dave, refreshing the "New Posts" page?

I really do need to get a life don’t I ?

Hi Brian,

It’s a VRAM issue

Regards
Dave

Hints here

http://www.primrosebank.net/computers/ ... repair.htm
http://www.primrosebank.net/computers/ ... _fault.htm

Great stuff!

Worthy of note is that MFX is now Y2K compliant and running CP/M 3.1 / CP/M Plus with date set to use UK region formatting

Also worth noting is that the time on Martin’s camera is wrong

Happy New Year to you too.

Great stuff - well done!

gunrock wrote: ↑27 Nov 2024 18:36 I think it's only Nassim who's been willing to take the angle grinder to the case for a similar mod.

I think that it must be a family thing

Hi, It’s almost certainly a VRAM fault. I suggest that you remove MFX and just use the MTX video output for faultfnding. Although it’s not consistent, on occasion, it looks like the “‘“ is being displayed instead of a space. That’s probably ASCII code 96 instead of 32, I.e., a 1 bit error in bit 6. ...

Probably the worst fault that you can have on an MTX is the "black screen of death", i.e., powering on the MTX to be greeted by a black screen and constant tone from the sound chip. The tone is generated by the sound chip (obviously) before it gets initialised early on in the ROM boot proc...

Great, glad that it’s working. I will correct the schematic at the weekend. I do just use a straight through (no twist) cable, albeit that the Red stripe is reversed at one end. The switches are in two sets of 4, so the drive A switches are SWA SW1-4 and the B drive is SWB SW1-4 Their settings depen...