The Sinclair QL Forum

I can sell you some Noel. I don't currently have any on ebay but I've sold 1,500+ ready cut pieces, specially for Sinclair cartridges. Here's a finished one with pics: https://www.ebay.de/itm/203169848312 Sure, that sounds good. Could you ship them on Monday if I pay for them today? I'm making anot...

Hi I bought some of these and with some trimming with a craft knife they look promising and I have had success with them saving a couple of carts from the bin. https://www.ebay.co.uk/itm/124121854703 Do you have an updated link, or at least a picture of it? I'd love to order some and I see several,...

Nice video, Noel! Unfortunately you hit the very same error on both QLs (one defect RAM chip, which is probably the secondmost common failure). It would probably have been interesting to see a different failure like on the bus transceivers, which are also a pretty common thing to fail. I guess on o...

Here's my first entry for this year's #QLvember repairing two QLs: https://youtu.be/0z4X4AMKlcs

Is YouTube embedding disabled on the forum for some reason? I can't get it to work.

And here's the promised video with the QL repairs (double feature!):


Edit: I can't see the embedded version. Weird. https://youtu.be/0z4X4AMKlcs

OK, replying to myself just in case someone else is interested in the future. All of this will be documented in a video I'll release probably next week anyway. I was reading through the Minerva manual and it talks about starting the RAM test in different places and to try doing a reset a few times t...

Right. I seem to have confirmed my own theory: Once I repaired the faulty RAM IC on the Issue 5, Minerva starts up and reports 128K! I'm off to find what could cause that. The multiplexors before the DRAM seem like a reasonable candidate. Or I suppose even the ULA that seems to be involved in memory...

All right, just a quick test: I moved the ROMs in the Issue 5 to the Issue 6 board and... same thing. Dot pattern and then white screen. So it's not the ROMs! Just for grins I'm planning on burning a 27C512 EPROM with the ROMs that came in that computer and trying it. I don't expect it to work now t...

If we assume that the DRAM and associated databus buffer/address multiplexors and the ZX8301 itself are all good - indicated by the fact that after replacing the ROM ICs with your EPROM board allows a successful start-up - and that the RAM test fails during the first phase (white-screen), then some...

Thanks to both of you! I'm glad that the behavior I saw was consistent with what Minerva was supposed to do. And that web site will definitely come in handy. Bookmarking it now. I'll have to experiment with the ROM. I guess next I'll burn an EPROM with the original ROMs and see if that starts up fin...