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Dave wrote: ↑10 Jun 2019 09:53 Point 8

As asked . . . .

Video Processor,
Yes,
Not particularly prone to failure, but it does happen
No, the original Mask ROMs are unobtainable
Yes

The video processor seems pretty robust.. mine survived high reverse voltages on the ground a couple of times and didn't blink!

To clarify 3) To return the machine back to MTX500 configuration you will need to look at the links near the PAL board marked LK6 and LK7. These are made using "loops" of wire soldering into holes on the circuit board. At the moment LK6 is set so that the '4' and 'C' holes are linked. You ...

OK, here's the scanned manual.

http://www.lingula.org.uk/~steve/share/ ... -Board.pdf

The PDF is too large to attach unfortunately.

CFX just says "Drive not found" and CP/M hangs when I try 'BB18'

Never mind. I've ordered a 64MB CF card from eBay.

I'll just use dd(1) under macOS. How do I configure the drive type?

So, it can't pretend to be a type "4B" Silicon disk then I s'pose? Oh well.

I'm probably being a bit thick but how do you format an SD card from scratch? Obviously you can't use reformat.com as you can' boot from an empty device and "USER FORMAT" and "USER SYSCOPY" have been disabled. I've got a nice 4MB (that's right, MB) CF card I'd like to format and ...

I notice that on Primrosebank that there's no RS232 Communications board manual... I have one and I'll see if I can scan it this week and upload a PDF.

Well, the address decoding's broken. If I have ROM B or ROM C in circuit at the same time as the Diag ROM then it doesn't start up. The EEPROMs test fine in the writer so it's the machine. I feel that there's probably a full set of chip replacements in order... but not until September. It's going ba...

Actually the CPU is fine. After pulling all the memory and fitting the Diag ROM I at least have something on the screen! Video RAM is fine, as is the VDP. The chips running the keyboard seem to be dead, quite possibly both the buffer and the other chip. One thing to note with the Diag ROM. If the RA...