Search found 1793 matches

by steve3000
Fri Aug 09, 2013 4:38 pm
Forum: hardware
Topic: Increasing memory speed on an A540
Replies: 13
Views: 1254

Re: Increasing memory speed on an A540

AndyMc1280 wrote:I have 16MB in my R260, and was happily using ADFFS until something on the board went *pop*.... still in at my friend's for diagnosis/repair.

Eeek, that sounds nasty :shock:

Was it the PSU? Hope it can be fixed quickly.
by steve3000
Fri Aug 09, 2013 7:04 am
Forum: hardware
Topic: Cleaning a floppy drive
Replies: 18
Views: 1382

Re: Cleaning a floppy drive

leenew wrote:It is a little strange though that 2 links are missing and definitely only 1 has come off.

I expect that missing link next to the yellow wire was pulled off by whoever fitted the yellow wire, as it looks a bit tight there ;-)
by steve3000
Wed Aug 07, 2013 7:05 pm
Forum: hardware
Topic: BBC Model B composite output
Replies: 4
Views: 656

Re: BBC Model B composite output

Interesting, what is jumper 39 supposed to do, other than distort the signal?
by steve3000
Mon Aug 05, 2013 8:58 am
Forum: hardware
Topic: Increasing memory speed on an A540
Replies: 13
Views: 1254

Re: Increasing memory speed on an A540

What do you mean by "refused to boot" - do you get a POST error signalled by flashing floppy drive light? (if so what was the error?) Is anything else driven off the 72MHz oscillator which could be causing the problem? And, as Tom asked, how much RAM is in there? Definitely try without any...
by steve3000
Sat Aug 03, 2013 9:03 am
Forum: software
Topic: Finally Got To Play Zarch
Replies: 15
Views: 3531

Re: Finally Got To Play Zarch

There's the other problem with modern monitors not being able to display the old modes. That's not an issue with the Pi, as the GPU determines what monitor you have attached, then all graphics output is reprocessed by the GPU and stretched/squashed to fit your monitor. Even low resolution 320 x 256...
by steve3000
Mon Jul 22, 2013 10:00 pm
Forum: hardware
Topic: Re: 3.5" drive head cleaning / aligning?
Replies: 2
Views: 564

Re: 3.5" drive head cleaning / aligning?

My Risc PC has not been 100% happy with floppy discs since it arrived from the big auction house on the net, about a month ago. It's had a drive replacement in the past and currently has a PC 3.5" drive fitted, along with a patch cable with a twist in the cable swapping pins 10 and 12, so drive...
by steve3000
Sun Jul 21, 2013 7:32 am
Forum: hardware
Topic: A3010
Replies: 28
Views: 3426

Re: A3010

flaxcottage wrote:Maybe though the drive just needs cleaning. A 3.5" cleaning kit is around a fiver.

Definitely try a drive cleaning floppy first. This has solved many drive issues with my old kit!

Also you may find your discs are at fault rather than the drive itself, particularly if they're 20+ years old.
by steve3000
Mon Jul 15, 2013 10:59 pm
Forum: hardware
Topic: So, here's a thing...
Replies: 26
Views: 4882

Re: So, here's a thing...

Nice one :D Great little optical mice these - thanks for the details Daniel! They work on Archimedes too, a bit fiddly to wire up but not too much effort once you get the connections the right way round. I've made a surprisingly similar joint, but left the PS/2 connector on there - might need to cho...
by steve3000
Sat Jul 13, 2013 9:02 am
Forum: hardware
Topic: A3010 Adelaide PCB troubleshooting
Replies: 163
Views: 8884

Re: A3010 Adelaide PCB troubleshooting

Ok, in that case still worth testing the new MEMC in an A3x0 or A4x0, in Mode 28, to confirm it's survived shipping, before mounting. The A540/R260 has the MEMC in a socket and runs at 12MHz - so if it came from one of these, then it would have been running at 12MHz in the past. After removing the o...
by steve3000
Sat Jul 13, 2013 8:04 am
Forum: hardware
Topic: A3010 Adelaide PCB troubleshooting
Replies: 163
Views: 8884

Re: A3010 Adelaide PCB troubleshooting

Good to see you're making progress! A faulty MEMC would certainly fit with the symptoms. Well spotted that! I've seen a MEMC fail before, but only a complete failure (ie. POST fail). Is there enough space to mount a socket on the Adelaide board for the replacement? Or are you going to have to surfac...
by steve3000
Tue Jul 09, 2013 8:43 am
Forum: hardware
Topic: Partially Working A4000 - Help!!
Replies: 59
Views: 4963

Re: Partially Working A4000 - Help!!

More than likely - it was sold by pimlights (Paul Middleton, ex Managing Director of RISCOS Ltd.) and was described as "This one was sprayed up black for use as a film prop about 10 years ago, and has been sitting on a shelf ever since." :shock: "film prop" indeed? which film wo...
by steve3000
Mon Jul 08, 2013 5:02 pm
Forum: hardware
Topic: Partially Working A4000 - Help!!
Replies: 59
Views: 4963

Re: Partially Working A4000 - Help!!

This morning the reset key has stopped working. I've just traced it through, and one gate on IC8 (a 74HCT14) has stopped working, with it's output stuck at 0v (reset inactive) regardless of it's input. The other gates (e.g. keyboard control and data) seem fine. I can't really explain this, it was w...
by steve3000
Sun Jul 07, 2013 8:53 pm
Forum: hardware
Topic: Partially Working A4000 - Help!!
Replies: 59
Views: 4963

Re: Partially Working A4000 - Help!!

Very strange indeed!

When your CLS code crashes, what error do you see and at which address?

Type *Showregs to list the register contents at the time of the error - are any of the registers corrupt, or having some unusual contents?

Steve
by steve3000
Sun Jul 07, 2013 8:47 pm
Forum: for sale / freebies
Topic: A5000. 4mb ram. Hard disk. Monitor.
Replies: 5
Views: 762

Re: A5000. 4mb ram. Hard disk. Monitor.

Thanks Marc, good to meet you today!

The A5000 is all set up and running smoothly this evening (now that my 'computer' room has cooled down enough to enter ;) )

Cheers,
Steve
by steve3000
Sat Jul 06, 2013 11:26 pm
Forum: hardware
Topic: Partially Working A4000 - Help!!
Replies: 59
Views: 4963

Re: Partially Working A4000 - Help!!

Just tried a quick test out on my A4000... 10PRINT"Default = ";:PROCtest 20SYS"OS_UpdateMEMC",0,&c0 TO original 30PRINT"450ns = ";:PROCtest 40SYS"OS_UpdateMEMC",64,&c0 50PRINT"325ns = ";:PROCtest 60SYS"OS_UpdateMEMC",128,&c0 70P...
by steve3000
Sat Jul 06, 2013 11:04 pm
Forum: hardware
Topic: Partially Working A4000 - Help!!
Replies: 59
Views: 4963

Re: Partially Working A4000 - Help!!

We used the OS_UpdateMEMC trick a lot to speed up RISC OS2 ROM access BITD... However under RO2, the values were interpreted differently (iirc), so you had to set both bits 6 and 7 to get 200ns. On RO3.1, setting both bits causes a crash. This lead to a lot of RO2 demos and some games crashing when ...
by steve3000
Sat Jul 06, 2013 9:25 pm
Forum: hardware
Topic: Partially Working A4000 - Help!!
Replies: 59
Views: 4963

Re: Partially Working A4000 - Help!!

Humm, most perplexing... The address line A14 should be fine, as your memory test should have used this. Also an error accessing a memory address would return 'Address exception' every time - and although you're seeing this occasionally, you're also seeing 'undefined instruction' a lot too... This i...
by steve3000
Sat Jul 06, 2013 7:13 pm
Forum: hardware
Topic: Partially Working A4000 - Help!!
Replies: 59
Views: 4963

Re: Partially Working A4000 - Help!!

Hi Steve, Thanks for sticking with me! No problem, it's always fun trouble-shooting these old machines. Sound and mouse pointer working is another good sign - both make intensive use of memory access to the first 1/2Mb of memory during interrupts, so if anything was wrong there, then the computer w...
by steve3000
Sat Jul 06, 2013 9:57 am
Forum: hardware
Topic: Partially Working A4000 - Help!!
Replies: 59
Views: 4963

Re: Partially Working A4000 - Help!!

I can make it crash easily, regardless of the mode: 10 CLS 20 GOTO 10 Yikes, that's not good at all. It seems that an intense burst of RAM writes (such as clearing the screen) is somehow affecting instruction execution from the OS ROM, causing an the processor to think it's seeing an undefined inst...
by steve3000
Sat Jul 06, 2013 8:54 am
Forum: hardware
Topic: Partially Working A4000 - Help!!
Replies: 59
Views: 4963

Re: Partially Working A4000 - Help!!

So, I'm wondering if this is starting to point the finger at something like excessive power supply noise, maybe down to old electrolytic capacitors not doing their job any more. My A4000 has so much noise on its power lines it keeps the house next door up at night. I really should replace its caps....
by steve3000
Fri Jul 05, 2013 8:47 pm
Forum: hardware
Topic: A3010 Adelaide PCB troubleshooting
Replies: 163
Views: 8884

Re: A3010 Adelaide PCB troubleshooting

What screen mode are you in? The mezzanine board runs the Arm2 at 12MHz and it was only ever meant to be a development board so I'd not be surprised if the Arm2 disliked a long run on an intensive soak test...(but I admit I've not actually heard of one fail) However, the memory and VIDC should be pe...
by steve3000
Fri Jul 05, 2013 9:11 am
Forum: hardware
Topic: Partially Working A4000 - Help!!
Replies: 59
Views: 4963

Re: Partially Working A4000 - Help!!

I expect your monitortype is set incorrectly (as a 'multisycn' monitor, rather than a SVGA/VGA screen) and so the test disc is entering a 15KHz mode...either that or your test disc is for an early Archimedes and not compatible with the A4000. To rule out the first, try booting to supervisor, using y...
by steve3000
Mon Jul 01, 2013 10:25 pm
Forum: hardware
Topic: Strange Risc PC video fault
Replies: 43
Views: 3000

Re: Strange Risc PC video fault

Hey that is great news!

It's always good to hear of another RiscPC saved from the curse of the leaked battery acid.

Have you checked all modes? Make sure you max. out the VIDC / VRAM with 800x600 in 24million colours as a final test.

Steve
by steve3000
Tue Jun 25, 2013 7:57 pm
Forum: software: games - high scores
Topic: Stardot High Score Challenge: Round 1 nominations
Replies: 24
Views: 2295

Re: Stardot High Score Challenge: Round 1 nominations

Sounds like great fun... And potentially very time consuming... But here are my three:

1) Duck!
2) Rouble Trouble
3) Cybertron Mission
by steve3000
Tue Jun 25, 2013 12:23 pm
Forum: hardware
Topic: Strange Risc PC video fault
Replies: 43
Views: 3000

Re: Strange Risc PC video fault

What does the VCO circuit actually do? I noticed it on the schematic, but I don't know what VCO stands for! Voltage controlled oscillator - it sets the frequencies used by the VIDC20 to generate the video and sync/lock signals for the monitor. If your monitor is locked at a sensible screen resoluti...
by steve3000
Tue Jun 25, 2013 12:14 pm
Forum: hardware
Topic: Strange Risc PC video fault
Replies: 43
Views: 3000

Re: Strange Risc PC video fault

I'm pretty sure you can't 'read' the palette - at least not from the VIDC20 chip, as its registers are write-only. The SWI will read the operating system's copy of the palette, which is stored in normal memory, in zero-page - but that's not really useful (ie. if the OS copy is wrong, then your compu...
by steve3000
Mon Jun 24, 2013 10:11 pm
Forum: hardware
Topic: PS/2 keyboard and mouse to Archimedes adapter
Replies: 21
Views: 3616

Re: PS/2 keyboard and mouse to Archimedes adapter

Interesting project indeed...! I've got the mouse and keyboard protocol translation software working, but I'm currently looking at the best way of handling the various incompatabilities between the PS/2 keyboard and Acorn layouts, like the caps lock/ctrl and double quote/@ swap. How was this handled...
by steve3000
Mon Jun 24, 2013 8:29 pm
Forum: hardware
Topic: Strange Risc PC video fault
Replies: 43
Views: 3000

Re: Strange Risc PC video fault

From the pictures and your description it sounds like the monitor is locked on to the screen - is that right? (if you have a monitor with on screen display, does it report a sensible screen resolution and refresh rate?). If so, the VIDC and clock are performing this far. Those pictures *really* look...
by steve3000
Mon Jun 24, 2013 5:33 pm
Forum: hardware
Topic: Formatting SD/CF cards for use on RISC OS 3.1
Replies: 33
Views: 17131

Re: Formatting SD/CF cards for use on RISC OS 3.1

Ok, I'd definitely recommend reformatting on the PC in case the card was/is bad - there are some good tools out there - I use sdformatter 3.1 from sdcard.org which claims to carry out a full format to the correct sd card specification. To 'verify' the card is ok, I use 'H2Testw' (search google) it m...
by steve3000
Mon Jun 24, 2013 4:35 pm
Forum: hardware
Topic: Formatting SD/CF cards for use on RISC OS 3.1
Replies: 33
Views: 17131

Re: Formatting SD/CF cards for use on RISC OS 3.1

Spoke too soon :( It works mostly, but I get enough "disc error 13" write errors when using the card on the A3000 to make it non-viable unfortunately. Oh dear...that sounds bad. Is the SD card known to be good? If you format it on the PC, can you fill it *completely* and then copy everyth...