Search found 1740 matches

by steve3000
Sun Feb 18, 2018 12:32 am
Forum: community projects
Topic: Earliest examples of each machine?
Replies: 30
Views: 2453

Re: Earliest examples of each machine?

we have all seen an issue 1 now that one has just sold on eBay for £331 just for the original board, not the rest ...pics or it did not exist : There's also a photo of an issue 1 pcb with the same style printed serial number in the PCW magazine review from Jan 82. It was #10, and (probably coincide...
by steve3000
Sat Feb 10, 2018 4:17 am
Forum: hardware
Topic: BBC micro black linear PSU repair
Replies: 12
Views: 268

Re: BBC micro black linear PSU repair

Wow, thanks for the detailed write up Mark! This is exactly what I need :) This came from an issue 2 beeb, and will be returning to it once repaired. I'm fairly sure some early issue 3's also had the linear type psu, but I don't recall ever seeing an issue 4 with one. I expect many of these linear P...
by steve3000
Fri Feb 09, 2018 11:54 pm
Forum: hardware
Topic: BBC micro black linear PSU repair
Replies: 12
Views: 268

Re: BBC micro black linear PSU repair

Thanks Ian! I actually found that page about 30 seconds before I read your post, so yet to read it, but it's definitely got some useful photos :) This is a pretty battered PSU tbh, it's suffered from a failed attempt to open and repair it in the past (annoyingly these PSUs were riveted together, no ...
by steve3000
Fri Feb 09, 2018 11:23 pm
Forum: hardware
Topic: BBC micro black linear PSU repair
Replies: 12
Views: 268

BBC micro black linear PSU repair

I'm trying to restore a broken "linear" type PSU from an early beeb. I can't find much about these in the service manual, so other than re-soldering the broken bits, I'm not sure where to start with testing this. Has anyone here tackled one before? See pictures below - first thing to addre...
by steve3000
Tue Feb 06, 2018 11:11 pm
Forum: for sale / freebies
Topic: Worth Taking a Look At
Replies: 2510
Views: 195010

Re: Worth Taking a Look At

Unfortunately the vendor does not have any provenance for the machine and no idea where he acquired it. My heart says get this machine and restore it. My head and probably my better half too say leave it to someone else. #-o Spotted this too, and thinking the same thing. Definitely a shame about th...
by steve3000
Tue Jan 30, 2018 10:51 pm
Forum: hardware
Topic: bbc-fdc from Jasper Renow-Clarke
Replies: 4
Views: 272

Re: bbc-fdc from Jasper Renow-Clarke

Nice work! Keep posted of how your tests go - are you going to try to connect to a 5.25" drive too? I've got one of these and all the components, but not yet assembled. I'm also planning to write some controller software myself... However, that's mainly because I'm planning to use this to read ...
by steve3000
Thu Jan 25, 2018 9:44 pm
Forum: hardware
Topic: RGB to HDMI using a Pi Zero and a small CPLD
Replies: 37
Views: 1077

Re: RGB to HDMI using a Pi Zero and a small CPLD

hoglet wrote:There is no video DAC - i.e. the TTL R G B inputs are just fed directly into the CPLD (so we have 1-bit RGB).

Ah, ok - very neat method! :)

So yes, you'd need 4 bits of each R/G/B to open up possibilities for other computers. Definitely something to explore if you can get DMA working in future.
by steve3000
Thu Jan 25, 2018 8:40 pm
Forum: hardware
Topic: RGB to HDMI using a Pi Zero and a small CPLD
Replies: 37
Views: 1077

Re: RGB to HDMI using a Pi Zero and a small CPLD

Great work! And so much scope for this type of approach. I suspect this would also do really well on the Archimedes, particularly for retro gamers wanting 320x256 @ 50 Hz. Definitely worth testing on an Archie :) Back to the beeb, when building the digitised frame, are you using the pixel colour cap...
by steve3000
Wed Jan 24, 2018 11:54 pm
Forum: programming
Topic: ADFS Format
Replies: 20
Views: 688

Re: ADFS Format

Brilliant resource, very useful to see this all in one place. Interesting to read about the 'G' format, I don't recall having seen that before, was it ever supported by RISC OS do you know? Or was it just theoretical?

Anyway thanks for sharing!
by steve3000
Wed Jan 24, 2018 9:17 pm
Forum: emulators
Topic: MODE 7 on RISC OS BBC Emulator 6502em
Replies: 14
Views: 442

Re: MODE 7 on RISC OS BBC Emulator 6502em

OK thanks, I will put the question out over there. As you've posted up the mdf, I've taken a look and I'm sure that should work....unless of course the latest RISC OS build for ARMX6 is filtering or further restricting available modes despite being in the mdf (possibly based on EDID data from the m...
by steve3000
Wed Jan 24, 2018 9:00 pm
Forum: emulators
Topic: MODE 7 on RISC OS BBC Emulator 6502em
Replies: 14
Views: 442

Re: MODE 7 on RISC OS BBC Emulator 6502em

jms2 wrote:I think I've tried mode 7 on my Raspberry Pi, running whatever version of Risc OS you get on there. I recall that it did not work.

It works very well on the Pi, *if* you load AnyMode :)
by steve3000
Wed Jan 24, 2018 12:12 am
Forum: emulators
Topic: MODE 7 on RISC OS BBC Emulator 6502em
Replies: 14
Views: 442

Re: MODE 7 on RISC OS BBC Emulator 6502em

As above, it looks like the software MODE7 emulation hasn't kicked in. What dimensions is MODE 7 in the mdf that you have? There must have been changes to the MODE 7 emulation at some point in the development of RISC OS 5, because it changed from low resolution 320x256 frame size to higher resolutio...
by steve3000
Wed Jan 24, 2018 12:05 am
Forum: software
Topic: Black Angel
Replies: 7
Views: 446

Re: Black Angel

Am I missing something or does travelling anywhere take ages? The first mission location for example took 40 mins to get too. My brother played this to death BITD. I do recall it taking a long time to complete some missions, but 40 minutes sounds much too long. Is there not a way to speed up time w...
by steve3000
Sat Jan 13, 2018 8:52 pm
Forum: general
Topic: Today I received.....
Replies: 4430
Views: 274355

Re: Today I received.....

A completely dead, but relatively unexpanded (apart from plug-in ICs) Issue 2 BBC model A: 20180110_232211.png 20180110_232122.png Not sure where to start with this one, but is nice to find one with no soldered-in sockets underneath. Last time I saw an issue 2 model A like this was in the early 90's...
by steve3000
Thu Jan 11, 2018 7:46 pm
Forum: off-topic
Topic: LOL DESCRIPTION
Replies: 582
Views: 54486

Re: LOL DESCRIPTION

https://www.ebay.co.uk/itm/253359708480

Love what he's done there! Definitely a rare combination :lol:
by steve3000
Sun Jan 07, 2018 10:50 am
Forum: hardware
Topic: Fault finding index
Replies: 86
Views: 17345

Re: Fault finding index

My recent beeb repairs: 1) http://stardot.org.uk/forums/viewtopic.php?f=3&t=12152 Seemingly random memory errors on an issue 3 beeb, likely caused by poorly fitting ICs or corrosion on IC legs... Solved by taking all socketed chips out, cleaning, and putting them all back in again. Also solved i...
by steve3000
Sun Jan 07, 2018 10:26 am
Forum: hardware
Topic: Broken Beeb - strange memory issue, what to try next?
Replies: 12
Views: 651

Re: Broken Beeb - strange memory issue, what to try next?

After running Exile (which I had loaded from disc) successfully, I decided to install a SD card and SuperMMC ROM so I could use this beeb as my main 8-bit computer for a while to ensure it was really working OK. However, on plugging in the SD card and SuperMMC ROM, nothing happened. No evidence of t...
by steve3000
Sun Jan 07, 2018 10:14 am
Forum: hardware
Topic: Broken Beeb - strange memory issue, what to try next?
Replies: 12
Views: 651

Re: Broken Beeb - strange memory issue, what to try next?

Almost 14 months on and this beeb is now working :) After confirming all voltages were correct and probing a bit further with my logic probe, I couldn't work out the cause of the seemingly random varying memory errors, so I packed up the beeb into the loft and went onto other projects. But then last...
by steve3000
Sun Jan 07, 2018 8:00 am
Forum: hardware
Topic: A3020 Restoration
Replies: 14
Views: 391

Re: A3020 Restoration

Unfortunately, I've often found that, along with track corrosion, the CMOS chip and/or the RTC crystal fail when a machine has been left unused for years :( IIRC, from the A3020 i repaired a few years ago, the RTC/CMOS chip is further away from the battery in the A3020 so this might not be such a p...
by steve3000
Sun Jan 07, 2018 7:50 am
Forum: emulators
Topic: Model A, OS 0.1 and disc interfaces
Replies: 10
Views: 601

Re: Model A, OS 0.1 and disc interfaces

By chance last night I came across an old Acorn ROM in my collection, labelled B02. Bit of investigating and it's OS 0.1. Popped it in the beeb, to find it didn't support BASIC 2, so I dug out BASIC 1 and tried again. This worked, now *FX0 reports "OS 0.1 EPROM" (which is slightly odd, bec...
by steve3000
Fri Jan 05, 2018 9:33 pm
Forum: hardware
Topic: A3020 Restoration
Replies: 14
Views: 391

Re: A3020 Restoration

As soon as possible dowse the affected corners in copious quantities of white vinegar, then agitate with a soft brush, this will neutralise the battery leakage. After 30 minutes or so of soaking, rinse with plenty of distilled water, then dry for a day or two in a warm room or boiler cupboard, befor...
by steve3000
Thu Jan 04, 2018 12:43 am
Forum: hardware
Topic: Think I'm loosing my (beeb) memory
Replies: 22
Views: 590

Re: Think I'm loosing my (beeb) memory

If you have not yet binned the defective DRAM chip, would it be possible to send it to me please. Certainly Mark, happy to. But first might be useful for me to attempt to fix my other dead beeb with potential memory problems, as this may provide more dead DRAMs... It's been sat in the loft for almo...
by steve3000
Wed Jan 03, 2018 6:55 pm
Forum: hardware
Topic: Think I'm loosing my (beeb) memory
Replies: 22
Views: 590

Re: Think I'm loosing my (beeb) memory

So this evening I pulled my spare (but currently dead for various other reasons...) BBC B out of the loft and borrowed one of it's socketted RAM chips to test as a replacement for the suspect IC55... ...And it worked! No more '$$$$'s in MODE7, or green lines in MODE2. :D :D :D Thanks both for your h...
by steve3000
Wed Jan 03, 2018 6:53 pm
Forum: hardware
Topic: Think I'm loosing my (beeb) memory
Replies: 22
Views: 590

Re: Think I'm loosing my (beeb) memory

After 2 hours of Exile running without a problem, I switched the computer off and on, and the screen was back full of '$$$$'s as before. Clearing the screen or changing MODE gradually improved the display, with '$$$$'s slowly disappearing with each CLS... Sometimes the computer would behave normally...
by steve3000
Tue Jan 02, 2018 6:06 pm
Forum: hardware
Topic: Think I'm loosing my (beeb) memory
Replies: 22
Views: 590

Re: Think I'm loosing my (beeb) memory

Interesting thought, yes, a short between address and data could certainly explain this... however I've just tested continuity between pins 13 and 14, and there's no indication of a short. Also interesting, the effect now seems to be intermittent. Always there on start-up (at the moment) but sometim...
by steve3000
Mon Jan 01, 2018 9:55 pm
Forum: hardware
Topic: Think I'm loosing my (beeb) memory
Replies: 22
Views: 590

Re: Think I'm loosing my (beeb) memory

Great work guys! Here's a picture of MODE7 on start up, note the pattern of 64 "$"s then 64 " "s. 20180101_210937.png Clearly it should be saying "Acorn TUBE 65C102 Co-Processor" etc. but if bit 2 was set on, you get "Egovn$TUFE$65G546$Go-Tvogewwov" - almost w...
by steve3000
Mon Jan 01, 2018 8:12 pm
Forum: hardware
Topic: Think I'm loosing my (beeb) memory
Replies: 22
Views: 590

Re: Think I'm loosing my (beeb) memory

In MODE 7 I see blocks of $$$$$ signs in some places where it should be black, suggesting certain bits are fixed 'on' in the upper 16k bank of RAM? Will post a photo later.
by steve3000
Mon Jan 01, 2018 5:27 pm
Forum: hardware
Topic: Think I'm loosing my (beeb) memory
Replies: 22
Views: 590

Think I'm loosing my (beeb) memory

I need some help tracking down the cause of a sudden memory problem which occurred today on my Issue 7 Beeb. I hadn't used my Beeb for a few months, and powered it up today to enjoy some 8 bit action before I have to return to work tomorrow... All was going well until I noticed the screen seemed to ...
by steve3000
Sun Dec 31, 2017 11:55 pm
Forum: hardware
Topic: RISC PC (Issue 1) will not play nice with any Podules (apart from a NIC in the NIC slot)
Replies: 2
Views: 205

Re: RISC PC (Issue 1) will not play nice with any Podules (apart from a NIC in the NIC slot)

Track damage (assuming you had battery leakage at sombre point?) or a dirty/corroded socket. I had the same from a RiscPC which I repaired a few years ago - I suspect the podule is being detected but it's ROM loader code isn't passing checksum after making it across to the computer. For me it was qu...
by steve3000
Sat Dec 30, 2017 12:49 am
Forum: for sale / freebies
Topic: Upgraded A310 and software bundle for sale
Replies: 11
Views: 638

Re: Upgraded A310 and software bundle for sale

That looks like a really high spec genuine A310 in original condition, with a nice software package too. I'm sure it would make a great system for an Archimedes enthusiast or beginner wanting to take a first step into retro 32bit Acorn computing! Looking at your photos, you should also mention that ...