The Sinclair QL Forum

Welcome!
That expansion looks really interesting!

Hello from Madrid as well!
I was delighted to read your post about your 1985 QL with Spanish keyboard. What a wonderful coincidence that we're both in the same city and share an interest in these classic machines!
I've also recently restored a QL and am currently in the exciting phase of adding new ...

Hi,

Sorry for the delay!

I have good news!!!

I finally found out what was happening inside the QL. By probing the signals on the processor, I discovered that when it crashed, BERRL (pin 40) was LOW!
How could this happen? That pin isn't used at all — it's just pulled up and exposed on the ...

Latest update:
The PSU is working fine, and the 7805 is also OK, but the situation remains the same.

I’ve observed that when the QL crashes, the DSMCL signal stays high (while KILLH is low). Curiously, everything seems to stop once DSMCL goes high. What’s more, this appears to be timed: during the ...

I’ve replaced both the 8302 and the 8049. There's been a slight improvement—now it occasionally manages to boot, and sometimes even responds to the reset button.

However, after a few seconds (no more than 5), the system starts to degrade and eventually crashes, showing random values in memory (and ...

Thanks! My QL has a JM ROM and it's an Issue 6 board. I’ll try replacing the 8302—fortunately, I have a spare one.

I suspect there may be a bus-related issue. The last time I powered it on, after the random pattern appeared, it made some unusual noises and displayed a vertical pattern before ...

Recently, I recovered a QL. A few days later, it started crashing at startup, and now it doesn't work at all.

The symptoms are as follows: when I connect the power supply, the video pattern appears on the screen, but unfortunately, it never completes. At the end of the random pattern, a white strip ...

Hi,
I'm back to the QL — it was my first computer many years ago, and now I have the opportunity to own one again.
Personally, I'm interested in hardware development, including QL expansion cards, so I'll be happy to help anyone who wants to dive into this adventure.
Thanks a lot to all of you!