The Sinclair QL Forum

Indeed, reseating the chips would be the first thing to do. i.e. do all non-destructive things first.

However, if this doesn't work then I would suspect the RAM. Minerva can't start under some RAM fault conditions, which is why I would suggest getting an EPROM written with my diagnostic ROM, which ...

Even if the C68 options to produce reentrant code are working, you can write functions, which you can call from assembler. But you cannot even write the "hello world" program from Kernighan & Ritchie, cause this uses printf(), which is in the standard library which is not reentrant.


But you ...

You would not normally use libc in romable programs anyway. Libc is not re-entrant and also relies on global state. This is true no matter the compiler.


It depends upon what you mean by "ROMable". If it's, say, a SuperBASIC extension which is installed in a ROM then I'd say it would be "ROMable ...

Hi
What do I need to look for to test these chips I had read that if on pressing F1 you don't hear the microdrive boot which it doesn't then it is unlikely to be the 8301 or is this rubbish.
Many thanks


The system isn't getting far enough to look at the function keys. It's not getting far ...

Hi,

The above is all good advice, but lack of display, in most cases is a faulty 8301

I would check the operation of CPU, 8301, 8302, 8049.


The second image shows a display, so the video output is fine.

It's probably a lower memory bank memory error, which is bad enough that Minerva can't ...

If you have the ability to write an EPROM then swapping the Minerva ROM on its board with a copy of my diagnostic ROM may give you more information about the fault.

Looks interesting.

For ease of use and longevity, would sprung pins be better than a pin header, with the SD carrier having contact plates onto which the pins press?

As for the ULA, I don't know if anyone has reverse engineered that one. It's probably quite simple.

A full memory test requires to:
1. Detect shorts
2. Fill the whole memory with at least 4 different basic patterns and read them are the same after it. "00", "11", "01", "10" and random. What takes some time.
3. In case of DRAM ICs, also check after a while the data remains (refresh).
4. If there ...

Another little update:

I removed the soldered IC3 and replaced it with a socket. The chip tests as OK in my Retro chiptester pro! But it clearly isn't, or it's at least marginal in some respect.

With IC3 completely missing I get just this screen using the diagrom:
20250706_182900(1).jpg
Sorry it ...