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I was unaware there was a 20 MHz version. I see no reason why swapping the crystal for 25 MHz wouldn't work. In principle the 486SLC upgrade should work. However there were often minor motherboard changes required when upgrading 386SX PCs to 486SLC (around cache coherency) and I'm not sure if anythi...

Omniflop should work. From memory RISC iX floppies are the same physical format as ADFS D/E.

I was 2 years old in 1989, so can confirm that was a while ago!

vexorg wrote: ↑Thu Apr 25, 2024 8:56 am

SarahWalker wrote: ↑Wed Apr 24, 2024 5:33 pm For the record, 72 pin SIMMs are around 25-30 years old, even DDR2 is nearly 20 years old. It's not the 90s anymore.

???
so I just dont bother adding more memory to a old system now?

Don't go into a shop and be surprised when they don't know what 30 year old SIMMs are?

For the record, 72 pin SIMMs are around 25-30 years old, even DDR2 is nearly 20 years old. It's not the 90s anymore.

(Didn't seem to be a better forum to put this in...) I'd like to announce Arcwiki, a wiki for all Arc/RiscPC stuff - https://arcwiki.org.uk . There have been discussions on Discord for a while now, so this probably doesn't come as a surprise to many. It's a work in progress so far, but I'd like it t...

I weekend pls

Have you configured it for StrongARM? That's the only CPU the recompiler works with.

Chuck the RAM in an old PC and run memtest86?

I looked up the memory map and memory mapping sections of the MEMC datasheet, and one thing that I had either forgotten or never paid any attention to was the possibility of 4K pages with MEMC. I started out with a 1MB A3000 which used 8K pages, but I imagine that A305 users would have been aware o...

As I have discovered so far, Archies won't like to be booted up without a good CMOS battery fitted. No way, both of mine (A310 and A3000) stayed stuck on a "black screen death loop": no beep, no keyboard NumLock on, just nothing but the speakers "crack"; Not true. Every Arc I've...

Out of interest, why the A5000 in particular?

unless you did something daft like buy the RiscPC without VRAM. Yep - my recollection is that VRAM was such an exotic thing that I didn't see a RiscPC with any VRAM at all for quite a long time. Interestingly, the serial number database suggests VRAM-less machines were very much in the minority.

The only real use I can see is making new ARM3 upgrades, given the processors are like hen's teeth. Does anyone know if anyone actually tried to make ARM6-based devices work on these machines, either at Acorn for prototyping purposes or elsewhere? Aleph One claimed to be entertaining the idea of an...

Naïve question: would a super fast ARM2 be just as interesting a project? Is it the ARM3 as such or just the faster performance which is of interest? (Is there software which particularly cares about the interior of the ARM3?) Just to quickly answer this question which has been missed; the ARM3 _is...

SID has an external audio output but I think can feed back into the computer via 1 MHz bus (I haven't used mine in a while!).

Printer port DAC doesn't feed back into the computer. Diagram is below for reference.

Absolutely nothing, IIRC other than the broken music it's basically the same as the Amiga & ST versions.

Oh, and one of the original 6522s is _definitely_ dead (OS boots but no keyboard, constant beep).

I'm mildly surprised that all the RAM seems to be good...

:) 20240106_155543.jpg So in total that was : - Fix the Friday afternoon soldering on the OS ROM socket - Clean out all the sockets with contact cleaner - Swap out IC14 (multiple times - I did originally do this back in November) - Swap over 6502s/6522s/6845s multiple times in the process of diagnosis

Progress! Swapped out IC14, test ROM is looking good now.

IC45 looks okay here. Going to work my way round the board...

The latch (IC15) for the teletext chip (IC5) and the VideoProc (IC6) are all on the DRAM side of IC14. If IC14 is not present, or is malfunctioning, the video system will malfunction. Good point, I hadn't spotted that. Tried running with S25 south. The "single bit set" tests (ie vertical ...

Some observations. The test ROM seems able to run indefinitely, suggesting fetching from ROM is working fine. While random corruption is present across all of RAM, it looks noticeably worse when A6 is low. The first bank of RAM also looks worse than the second, though corruption does still occur the...

Finally got round to testing again with tricky's test ROM. Looks a tad unhappy to me. Annoyingly the exact corruption / failures vary between runs. I've seen it fail to display the Frogger screen correctly, and produce a rolling MODE 0 display. 20240106_113105.jpg 20240106_113108.jpg 20240106_113056...

That would explain the slightly off feel! Pity Superior couldn't splash out for a copy of Amiga Ninja Remix for comparison. The BBC/Electron conversions are a bit of a technical miracle but not really all that great to play.

I'd have said the Amiga graphics probably fit the game better; the Arc graphics are a tad garish. The Amiga version also has a better feel imo.

I went for where ChannelOut is 0-255, ChannelIn is 0-15. Probably not very accurate but looks alright to my eyes.

I've usually just thrown together a converter as-and-when required. I could probably put a generic tool together.

I still update the numbers periodically, for most machines there's not much that will move the needle though.

Full weekend for I pls.