Search found 1943 matches

by steve3000
Fri Jan 11, 2019 11:01 pm
Forum: hardware
Topic: A3000-to-A5000 ROM adapter
Replies: 18
Views: 497

Re: A3000-to-A5000 ROM adapter

RobC wrote:
Fri Jan 11, 2019 10:06 pm
I think the two halves of an 8MB SIMM have separate RAS signals
Yes, that's what I understood was the case for 8mb SIMMs as they are dual-ranked...but I will be reading up a bit more thoroughly on the subject before making any plans :)
by steve3000
Fri Jan 11, 2019 4:17 pm
Forum: hardware
Topic: A3000-to-A5000 ROM adapter
Replies: 18
Views: 497

Re: A3000-to-A5000 ROM adapter

RobC wrote:
Fri Jan 11, 2019 4:08 pm
I believe that the 4MB upgrade in my A3000 might well be the SIMM type so I could possibly put in an 8MB SIMM and just wire across the extra address line :idea: =D>
I'm thinking of trying exactly the same, once can work out the required signals needed to patch across. Will keep you posted.
by steve3000
Fri Jan 11, 2019 12:48 pm
Forum: hardware
Topic: A3000-to-A5000 ROM adapter
Replies: 18
Views: 497

Re: A3000-to-A5000 ROM adapter

Makes sense...so there should only be a handful of signals needed between the 8mb RAM and twin MEMC board? In which case, if you could replace the 4mb RAM in the A3000's 4mb upgrade with 8mb, then wire across the necessary signals (including the extra address line) to a twin MEMC board, you could av...
by steve3000
Thu Jan 10, 2019 11:24 pm
Forum: hardware
Topic: A3000-to-A5000 ROM adapter
Replies: 18
Views: 497

Re: A3000-to-A5000 ROM adapter

Well, looking at an A3000 last night, there is actually more height clearance under the keyboard than I thought there was. So I think you could get enough height, either but directly mounting the converter pcb to the motherboard or the 4-8mb ROM card to the converter. However I'm now thinking it's t...
by steve3000
Wed Jan 09, 2019 8:44 pm
Forum: hardware
Topic: A3000-to-A5000 ROM adapter
Replies: 18
Views: 497

Re: A3000-to-A5000 ROM adapter

Still need to desolder the original MEMC1A from the A3000 PCB and fit a socket but I managed to remove the ARM2 and add an ARM3 upgrade. Also need to consider the clearance - you'll need to fit the A5000 expansion under the A3000 keyboard, and it'll have to avoid other components. Might just be pos...
by steve3000
Wed Jan 09, 2019 5:54 pm
Forum: hardware
Topic: A3000-to-A5000 ROM adapter
Replies: 18
Views: 497

Re: A3000-to-A5000 ROM adapter

Great work!
by steve3000
Wed Jan 09, 2019 2:58 pm
Forum: general
Topic: Looking for A3000 motherboard
Replies: 3
Views: 128

Re: Looking for A3000 motherboard

Brilliant! I look forward to reading more as/when you wrote up :)
by steve3000
Wed Jan 09, 2019 2:15 pm
Forum: general
Topic: Looking for A3000 motherboard
Replies: 3
Views: 128

Re: Looking for A3000 motherboard

Can't help with a spare mobo unfortunately, but interested how you cleaned up the battery damage - looks like you've take the tracks back to copper? And nice closeup picture - what's that taken with? My mezzanine A3010 has terrible battery damage, but after manually rewiring about 15 tracks, it boot...
by steve3000
Tue Jan 08, 2019 8:21 am
Forum: emulators
Topic: Arculator & Risc OS 2.0
Replies: 3
Views: 233

Re: Arculator & Risc OS 2.0

Never managed it, but not tried much. RISC OS 2 doesn't support IDE without external hardware, so I assumed no support for HDD under RO2 - unless there is a podule emulation of IDE, or ST506 HDD emulation?
by steve3000
Tue Jan 08, 2019 8:18 am
Forum: hardware
Topic: "Arcflash" A3000/A3xx/A4xx/A5xx/A5000 in-system programmable ROM -- any interest?
Replies: 69
Views: 2006

Re: A3000 in-system programmable ROM -- any interest?

myelin wrote:
Tue Jan 08, 2019 1:46 am
so I now have all the classic OS images working :)
Great! Does RO3.19 work ok too? (No reason it shouldn't, but it is a but different, and the final official RISC OS release that ran pre-RiscPC)
by steve3000
Mon Jan 07, 2019 8:03 pm
Forum: hardware
Topic: "Arcflash" A3000/A3xx/A4xx/A5xx/A5000 in-system programmable ROM -- any interest?
Replies: 69
Views: 2006

Re: A3000 in-system programmable ROM -- any interest?

Another option would be to see if I can allow the host machine to switch banks, so it can access the whole 16MB (maybe with a fixed 1-2MB and a paging area above that). I like the sound of this, especially if you could do a keyboard scan at startup and respond to say f1, f2, f3, f4 pressed, by sele...
by steve3000
Mon Jan 07, 2019 1:31 am
Forum: hardware
Topic: "Arcflash" A3000/A3xx/A4xx/A5xx/A5000 in-system programmable ROM -- any interest?
Replies: 69
Views: 2006

Re: A3000 in-system programmable ROM -- any interest?

WOW! Well done! =D> Really great to see how you have developed this. How does the ROM switching work (or is this work in progress?). For Arthur, I found 0.3 to be the most challenging to get working, because as you've noticed, it doesn't support >1mb. For Arthur 1.2, as I recall, this worked in my A...
by steve3000
Fri Jan 04, 2019 11:27 pm
Forum: off-topic
Topic: Solder/flux recommendations
Replies: 10
Views: 274

Re: Solder/flux recommendations

Thanks for the recommendations, I'll definitely go for lead solder then! Arc would have been leaded. CPC sell multicore 60-40 still, that's what I've found to be the best? I have a US brand too which doesn't wet as well... I use no-clean liquid flux The multicore 60-40, 0.7mm from CPC looks good and...
by steve3000
Thu Jan 03, 2019 11:37 pm
Forum: off-topic
Topic: Solder/flux recommendations
Replies: 10
Views: 274

Solder/flux recommendations

I'm almost out of solder and wondering what people recommend for retro-computer work. My last 100g reel of lead-free came from my local Maplin store, so I need alternatives... I'm planning to do some SMD removal (to replace dead IOC from my A4 and a dead VIDC from my old A5000) and some extensive re...
by steve3000
Wed Jan 02, 2019 7:22 pm
Forum: hardware
Topic: Puzzling graphics glitch on my Beeb
Replies: 45
Views: 1201

Re: Puzzling graphics glitch on my Beeb

Not replaced the socket yet, but after (accidentally) leaving the computer running all day today, while I was at work - I noticed the glitch is not restricted to MODEs 4 and 6! Seems all >2 colour modes are affected except MODE 7. Selecting background COLOUR 129 in MODE 1 or MODE 5, then typing CLS ...
by steve3000
Tue Jan 01, 2019 11:56 am
Forum: hardware
Topic: Sharing some hardware drivers.
Replies: 3
Views: 184

Re: Sharing some hardware drivers.

I'm sharing a few of my hardware drivers for some of the rarer hardware. In return, I'd dearly love a driver to add to the collection for the soundcard Ace RiscBlaster that I've recently purchased from ebay. Great effort Paul, thanks for sharing these - it highlights that we definitely need an arch...
by steve3000
Mon Dec 31, 2018 12:25 pm
Forum: hardware
Topic: Puzzling graphics glitch on my Beeb
Replies: 45
Views: 1201

Re: Puzzling graphics glitch on my Beeb

Update - still not solved but continued incremental improvements. This weekend I de-soldered all PCB power connectors, removed, cleaned and refitted. I spotted that the central 0v connector had a hairline fracture so I replaced this. I also re-soldered the ULA socket in case of dry joints, but I did...
by steve3000
Sun Dec 30, 2018 8:05 pm
Forum: hardware
Topic: A310 keyboard left shift key awkwardness
Replies: 4
Views: 110

Re: A310 keyboard left shift key awkwardness

Has anyone else observed this, or better still, fixed this? Something looks wrong there with the amount of flex in your key... My A310 keyboard (next to me at the moment) doesn't behave quite like this - the left shift does flex slightly, but even when pressed at the far right of the left key, it s...
by steve3000
Fri Dec 28, 2018 7:32 am
Forum: hardware
Topic: Puzzling graphics glitch on my Beeb
Replies: 45
Views: 1201

Re: Puzzling graphics glitch on my Beeb

91 ohms! :shock: Humm... re-measured and I get 18 ohms. Can't figure out how I previously measured 91... but that's what I'd noted down. IIRC, issue 3 and earlier boards did not link the three different +5V/Vcc supply networks together, while issue 4 and issue 7 boards do link them. Seems correct, ...
by steve3000
Thu Dec 27, 2018 1:35 pm
Forum: hardware
Topic: Puzzling graphics glitch on my Beeb
Replies: 45
Views: 1201

Re: Puzzling graphics glitch on my Beeb

The resistor is the big one next to the video ULA. As in the biggest resistor on that part of the PCB. Dooh! Typical. I overlook the most enormous resistor... Anyhow, it measures a nice round 18.0 ohms. :) Voltage measured at pin 15 is 2.04v. Resistance from pin 15 to the power connector is 91 ohms...
by steve3000
Thu Dec 27, 2018 12:12 pm
Forum: hardware
Topic: Puzzling graphics glitch on my Beeb
Replies: 45
Views: 1201

Re: Puzzling graphics glitch on my Beeb

Well it's not solved yet but as of today, I can run Elite happily for hours with no interference present, providing the lid is off the computer (this was not the case when I started this thread). However, shortly after placing the lid back over the computer, the interference begins to appear as the ...
by steve3000
Thu Dec 27, 2018 12:10 pm
Forum: hardware
Topic: Puzzling graphics glitch on my Beeb
Replies: 45
Views: 1201

Re: Puzzling graphics glitch on my Beeb

Is the video ULA socket the original or has it been replaced? As well as the item/points raised above, also check / test the following: S26 link and it’s connections, R114 (18 ohms), diodes D16, D17 and D18, C47 (10uF), Plus all their connections. And the voltage at ULA pin 15. Is the 16MHz clock w...
by steve3000
Tue Dec 25, 2018 11:08 pm
Forum: software: other
Topic: Beeb Xmas music mix
Replies: 3
Views: 345

Beeb Xmas music mix

I finally re-found this excellent Xmas music mix for the Beeb from 1990, which I vividly recall annoying my parents with by playing repeatedly BITD. Since coming back to the beeb a few years ago I'd searched on and off for this demo, but had no idea what it was called or how/where I came across it, ...
by steve3000
Mon Dec 24, 2018 9:31 am
Forum: hardware
Topic: Puzzling graphics glitch on my Beeb
Replies: 45
Views: 1201

Re: Puzzling graphics glitch on my Beeb

Although I've tracked the glitch down to the ULA, I haven't solved the problem yet... After fitting a modern heatsink to the ULA, using a sensible amount of thermal paste, the computer runs Elite nicely for a good 20 minutes with the lid on...but then the interference still appears! :( Even with the...
by steve3000
Mon Dec 24, 2018 9:23 am
Forum: hardware
Topic: Puzzling graphics glitch on my Beeb
Replies: 45
Views: 1201

Re: Puzzling graphics glitch on my Beeb

Good advice Mark. For modern components designed to use heatsink you only need the thinnest amount of thermal paste to cover any microscopic imperfections on the IC surface and heatsink surface (on a modern CPU and heatsink this will typically be < 0.1mm film of paste) to avoid the paste becoming a ...
by steve3000
Sun Dec 23, 2018 12:44 am
Forum: hardware
Topic: Puzzling graphics glitch on my Beeb
Replies: 45
Views: 1201

Re: Puzzling graphics glitch on my Beeb

After a break, I've come back to my beeb with the graphics glitch, and tonight I think I've pinpointed the cause of the glitch... In your case, I wonder if the Video ULA is over-heating as well. Is the heatsink loose? Although I'd refitted the heatsink, using new thermal compound and confirmed the h...
by steve3000
Sat Dec 15, 2018 7:18 pm
Forum: hardware
Topic: ADFS/ZIDEFS format for using CF card with PC?
Replies: 3
Views: 200

Re: ADFS/ZIDEFS format for using CF card with PC?

RISC OS on RPi does exactly this on a SD card, by having a DOSFS image drive present in the ADFS map (inside the !Boot directory), which is physically mapped to a real DOS partition. So if you wrote the 2Gb RISC OS 5 SD image to a CF card this would probably achieve what you want, providing you were...
by steve3000
Fri Dec 07, 2018 7:38 am
Forum: general
Topic: Today I received.....
Replies: 4958
Views: 356782

Re: Today I received.....

You'll be fitting it, to a BBC I presume? I'll be fitting this to my main beeb over Christmas, providing I can fix the ongoing interference issue with the beeb... @steve3000 could you post a ROM dump and scan of the manual please [-o< Certainly can. Will be in a week or so as away from home now. :)
by steve3000
Sun Dec 02, 2018 1:51 pm
Forum: hardware
Topic: Puzzling graphics glitch on my Beeb
Replies: 45
Views: 1201

Re: Puzzling graphics glitch on my Beeb

That turned out to be the confluence of three things: 1 - slightly loose motherboard power spade connectors 2 - poor connection to Video ULA 3 - lowish power supply voltage (~4.65V) As Ed mentioned earlier, the fix was to clean/tighten the spade connectors (which helped a bit) and then fit a turned...
by steve3000
Sun Dec 02, 2018 1:02 pm
Forum: projects
Topic: Starting a port of Stunt Car Racer...
Replies: 22
Views: 882

Re: Starting a port of Stunt Car Racer...

Wow! That's wonderful to see on the beeb! =D>