I actually had an ARM3 upgrade that I'd picked up a few years back, intending to upgrade my RISC OS 2 A310, but I'd since decided I quite like the originality of the ARM2 machine, so I got in touch with Costa (Joka80) and we ended up talking about his plans for his A3000. To summarise a lot of discussion, he had big plans – with ultimate intention of making his 4mb, ARM2, A3000 (which he'd owned since new) into the fastest, most capable A3000 in existence! However, at that point his A3000 was not even functioning (due to battery leak damage) and he also needed to find someone who could actually carry out the required modifications.
I quite liked the idea of a super fast A3000 and was looking for a hardware challenge to occupy the winter evenings, so as well as being able to supply the ARM3 upgrade he wanted, I offered to have a go at helping with the modifications to the PCB to fit the ARM3, and possibly some more modifications if I had time...
What eventually happened? Seven months later and what started with repairing and modifying an A3000 to install a 25MHz ARM3, has progressively turned into the biggest, most complex hardware challenge I've taken on. Several members of the forum have also contributed through time, advice and indeed components to different aspects of this build (especially myelin and RobC, without who this would not have been possible – as you'll see) and now as this project approaches completion, I'm very pleased to say that I believe we have achieved what Costa asked, and I hope to share here some of the interesting stages of development of what is probably the fastest, most capable A3000 ever built
So first, as a taster, here are a few photos and a summary of what Costa's original 4mb, ARM2, A3000 is now running under its lid.
Monster A3000 as of 26th July 2019:
- ARM3 upgrade, running at 48MHz (via an on-the-fly reprogrammable PLL clock generator)
- 8mb RAM upgrade (A5000 8mb upgrade modified to fit A3000)
- Custom built 1.6Mb High density floppy disc upgrade & FDD
- Unfiltered stereo sound to internal speakers
- Wifi USB mouse via internal fitted “Smally” mouse adaptor