The Sinclair QL Forum

Thanks Stephen

I have a spare one of those so I may give it a try

jobdone wrote: Wed Aug 20, 2025 6:06 am I think the easiest option is to use the pcb from here https://github.com/alvaroalea/QL_Rom_Cartridge . the full rom cartridge version.

Thanks, I'd got the wrong end of the stick about what rom cartridge was being used

stephen_usher wrote: Sun Jun 08, 2025 3:07 pm Hack a ROM cartridge so that it passes all address lines through to the EEPROM and voila!

Hi Stephen,

Do you have an idiots (that's me) guide to this please?

Many thanks
Tony

I've got something similar, but my main stockpile will be Fuller's HSB

I was reading thru the SBASIC online manual and came across the res_size routine for the SGC

I picked one of the programs I couldn't get to run on the JS/SGC and used "res_size 512", instead of "reset 512" (which works without the SGC) and the program ran (much too fast of course!)

Will go back ...

And have now confirmed I2C is working ok too

dilwyn wrote: Tue Aug 19, 2025 12:11 pm Nice work t0nyt. Great to see you persisted with your efforts. And thanks for the picture.

Thanks Dilwyn

Have now fitted it in my main QL and all working (not tried I2c yet though)

This picture was taken before I moved it to the left hand ROM socket

(Don't look too closely at any visible soldering)

Thanks for all the advise

This is the Switchable ROM waiting to be fitted (cabling is Switch for JS/Minerva 1.98, Battery & I2C 'D' harness to match my BBC B cabling so that all I2C stuff can just be swapped between them)


IMG_4966.jpeg


And the underside showing the 74LS133 installed upside down on the bottom of the PCB ...

Jackpot…

I realised that there was something I hadn’t tried with the socketless version where JS was working but Minerva hung with green lines

I fitted the battery and now it works!

Next up will be to test the RTC/i2c are working ok and then I can fit it permanently in my main QL