Search found 1727 matches

by steve3000
Sat Jan 13, 2018 8:52 pm
Forum: general
Topic: Today I received.....
Replies: 4348
Views: 264369

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: 52680

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: 84
Views: 16820

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: 546

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: 546

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: 313

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: 510

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: 313

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: 490

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: 490

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: 490

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: 490

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: 490

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: 490

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: 490

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: 133

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: 8
Views: 456

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 ...
by steve3000
Tue Dec 05, 2017 7:34 am
Forum: hardware
Topic: Switchable/dynamic/expanded RISC OS
Replies: 25
Views: 731

Re: Switchable/dynamic/expanded RISC OS

Has anyone, ever, put a 4Mbyte ROM set in an Archimedes, or heard of anyone ever doing it? Yes, I've done it (which is why I was suggesting this on the other thread :)) LA21 is present at the sockets on the A540 and latter (mostly selected via a link), so that's the A540, A5000, A4, A3010, A3020, A...
by steve3000
Tue Dec 05, 2017 1:04 am
Forum: hardware
Topic: Switchable/dynamic/expanded RISC OS
Replies: 25
Views: 731

Re: Switchable/dynamic/expanded RISC OS

Thinking more about this especially considering the above discussion, and the fact that going larger than current RISC OS 3 ROMs, while OK for most Archimedes computers, won't be universally easy as some early computers will need modifications - I'm definitely leaning towards two project approach. (...
by steve3000
Tue Dec 05, 2017 12:44 am
Forum: software
Topic: Roll your own RISC OS 3.1x
Replies: 3
Views: 768

Re: Roll your own RISC OS 3.1x

Ooh very nice :)

Do the build tools include calculating the ROM checksums and a tool to generate 'striped' 8 bit or 16 bit ROM image files for burning? (The later is simple to write if not...)
by steve3000
Sun Dec 03, 2017 6:14 pm
Forum: for sale / freebies
Topic: New Aneng AN8000 Digital multimeter £10 posted UK
Replies: 1
Views: 136

New Aneng AN8000 Digital multimeter £10 posted UK

As per the title. I accidentally ordered two of these rather neat, entry-level digital multimeters, due to a slight ebay ordering mix up. So here's my spare one for sale. 20171203_151349.jpg Supplied as in picture, all brand new, just needs 2 x AAA batteries. £10 incl. UK postage, if paid by paypal ...
by steve3000
Sun Dec 03, 2017 5:26 pm
Forum: hardware
Topic: RISC OS 3.20 ROM's?
Replies: 119
Views: 3337

Re: RISC OS 3.20 ROM's?

Good point. I ordered some 27C160's from futurlec.com last year and they're still listing them as available now. reichelt.com also lists them as available, but 31-41 day delivery suggests shipping from China. But yes, the more mainstream suppliers don't seem to list these, so would need to confirm a...
by steve3000
Sun Dec 03, 2017 3:46 pm
Forum: hardware
Topic: RISC OS 3.20 ROM's?
Replies: 119
Views: 3337

Re: RISC OS 3.20 ROM's?

Really interesting topic! Great work so far Jon, Jeffrey and all. Considering the squeeze on space trying to fit within the original 2mb RISC OS 3 ROM size, I think this could be a opportunity to use a larger EPROM and create a 4mb RISC OS 3.2. I looked into this very briefly a while back, but never...
by steve3000
Mon Nov 20, 2017 10:11 pm
Forum: for sale / freebies
Topic: Worth Taking a Look At
Replies: 2486
Views: 188563

Re: Worth Taking a Look At

Thanks for the hint with the two jumpers to set. But it still remains the same, no reaktion, power led goes on and thats it. Do the keyboard lights come on/off? What happens when pressing reset? What i have recognicsed is, that there is no real serial number on the machine, only handwriting on the ...
by steve3000
Mon Nov 20, 2017 9:38 pm
Forum: wanted
Topic: Adapter and device that reliably produce Disc Error 23
Replies: 14
Views: 548

Re: Adapter and device that reliably produce Disc Error 23

I would have thought it's specific to the adaptor as that's what implements the interface, however I have a few SD cards I can try over the next few days... I've certainly seen this behaviour from some of the SD adaptors I have, as I've also seen Disc Error 23, but I can't be sure I ever carried ou...
by steve3000
Mon Nov 20, 2017 9:23 pm
Forum: for sale / freebies
Topic: Worth Taking a Look At
Replies: 2486
Views: 188563

Re: Worth Taking a Look At

Hi! I'm the one who bought this strange A540 with the eproms that have Markes by hand. The problem is, the machine had seriously battery leaking problems and is not booting up. Dead :cry: As Ian says, the pictures show that this A540 has had some previous expansions (most likely a genlock or colour...
by steve3000
Thu Nov 16, 2017 12:54 pm
Forum: hardware
Topic: A5000 Disc Error 21
Replies: 2
Views: 147

Re: A5000 Disc Error 21

If you don't hear the usual spin up and heads engaging noise at startup then this is likely to be a failing drive, but first double check everything, especially that the cable is correctly inserted and not shifted along by one row of pins. I've had a few drives from 90s computers fail. It is possibl...
by steve3000
Sun Nov 12, 2017 9:08 am
Forum: wanted
Topic: Adapter and device that reliably produce Disc Error 23
Replies: 14
Views: 548

Re: Adapter and device that reliably produce Disc Error 23

Hi Jon, I have SD-> IDE adaptors which consistently produce disc error 23 when connected to an A5000. I don't know if they do the same on a RiscPC though (if this is what you're working on?). The adaptors all have a single IC with ST368 and/or Sintechi written on them, and are currently what you rec...
by steve3000
Mon Nov 06, 2017 12:10 am
Forum: hardware
Topic: Another A5000 restoration....
Replies: 10
Views: 505

Re: Another A5000 restoration....

Well done for getting so far! It's easy to give up on these and I know from experience they can be really frustrating at times. I repaired an A5000 with faulty floppy drive in the past, cause was IC42 in that case, but I'm sure the symptoms were different to yours. I vaguely recall the drive was det...
by steve3000
Sun Nov 05, 2017 10:13 pm
Forum: for sale / freebies
Topic: Worth Taking a Look At
Replies: 2486
Views: 188563

Re: Worth Taking a Look At

IanS wrote:
danielj wrote:That backplane looks ostensibly identical to an A5000 backplane?

d.

The connector that plugs into the motherboard is on the other side.

Also the A540 backplane, at least mine, is incredibly flimsy, flexing at the slightest pressure... Whereas my A5000 backplane is much more sturdy. :)

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