Hardware: Installing a Sinclair QL ROM Switcher

It's time to open up the Sinclair QL, this time we're going to be installing a ROM switcher which will allow us to replace the existing ROM with the more advanced Minerva but also allow us to switch to a ROM with Toolkit 2 built-in if necessary.

Chapters
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00:00 Intro
00:19 Why we're doing it
01:44 Taking it apart
02:38 Analysing the job
03:51 Removing the ROMS
05:00 Installing the switcher
06:05 Reassembling
06:37 Testing the ROM
09:53 Outro + Patrons

Background music: Walk through the park by TrackTribe

[BitRetroJournal]

I believe that ROM board only lets you switch on/off Toolkit 2 (a 16K add on to the 48K main ROM) but not the actual OS ROM, so you can configure Minerva with or without Toolkit 2...the reason is that when switched on you can't plug anything else (like say an ICE ROM or the upcoming QL-SD ROM) into the ROM port in the back.

That last error you got is most likely a corrupt .MDV file on your SD card since it saw it as bad or changed medium. You can check it by just typing "copy mdv3_cavern_code to con" excluding the quotes, and that should be able to print the entire binary code to your console (may take a bit of time)...if it fails then you know it's corrupt (or maybe juts needs a resetting of the vDrive, by power cycling the QL, which can occasionally flake out).

BTW, I'm surprised it didn't give you an "out of memory" error since you ran it twice, doing a second call to ALCHP setting aside 72K...usually that first 72K is still set aside before a reboot (requiring 144K free and it's only a 128K system with about 86K available). I don't think Minerva clears all memory on a re-run of a program...the JS/JSU ROM doesn't.

[ukzoinks]

Love my QL and recently got my Qdrive and mdv1 remapper although I haven’t tried them yet. I got my QL from new and it had the early AH ROM (the first ROM that didn’t need the external dongle). I knew that wouldn’t work with the Qdrive so I bought some JS ROMs ready to try. But seeing this video, I hadn’t been aware of the Minerva switcher Brexit has made it hard to get one, but hopefully I have one on the way from a German seller.

[PondersRetroGoodness]

It was fine this time but I always test before replacing the screws. I've learned this the hard way ;)

[RetroBytesUK]

So I'm not the only one that scavenges parts from my old experiments then.