exxos's Atari, Amiga & retro forum

stephen_usher wrote: 05 Dec 2023 10:50 At last the capacitors I ordered over a week ago are out for delivery. Not that I need them now.

:crossed1: :crossed2: :crossed1:

One step forward, one step back last night.

Seeing as the AM27C256 chips had arrived I wrote the image of the OPD mask ROM I'd extracted over the weekend onto one of them and fitted it the machine. The result was that it started from cold.

Everything seemed OK until I tried to format a Microdrive at which point, before it had started the drive the "Housekeeping" program crashes, suggesting that there's corruption somewhere in the ROM. *sigh*

Oh, and still no advance on getting the QL(s) to write cartridges that the OPD can reliably read, even with my second QL I get the same issues.

That's gotta be annoying @stephen_usher, sounds like you need to fetch the other QL down just to rule out a failure on this one.

Yeah, I've tried with both machines.

Someone posted a set of their ROM images on the QL Forum so I checked the XBAD03 image against the one I extracted from the dying mask ROM, and they're the same, so obviously the inability to format is a new problem.

I spent yesterday evening using the information I have, including images of the PCB layout (top and bottom) to reverse engineer and document in KiCAD the Computer One floppy disk interface with the view to re-creating it. Probably about a third of the way there.

P.S. This is the PCB image I have (I combined the separate layers in GIMP).

Other than the pull-ups and decoupling caps the schematic is finished. Phew!

Today I received...

A QIMSI. A "hard drive" and USB-PS/2 keyboard and mouse unit for the Sinclair QL which plugs into the ROM port.


Once I get a 3D printer I can make a case for it.

stephen_usher wrote: 08 Dec 2023 11:56 Today I received...

A QIMSI. A "hard drive" and USB-PS/2 keyboard and mouse unit for the Sinclair QL which plugs into the ROM port.


IMG_3475.JPG


Once I get a 3D printer I can make a case for it.

Looks interesting, it'd be good to see it running.

rubber_jonnie wrote: 08 Dec 2023 12:01 Looks interesting, it'd be good to see it running.

Same here. I won't have time tonight and anyway I need an SD card, which I've ordered from Amazon with delivery tomorrow. I won't have much time tomorrow either as I'm in work most of the day upgrading one of our virtual windows servers (2012R2 -> 2019 -> 2022).

stephen_usher wrote: 08 Dec 2023 12:18

rubber_jonnie wrote: 08 Dec 2023 12:01 Looks interesting, it'd be good to see it running.

Same here. I won't have time tonight and anyway I need an SD card, which I've ordered from Amazon with delivery tomorrow. I won't have much time tomorrow either as I'm in work most of the day upgrading one of our virtual windows servers (2012R2 -> 2019 -> 2022).

Very, interesting. Waiting to hear how you get on with the QIMSI. If its any good may have to get one for my QL.