Search found 205 matches

by philb
Tue Oct 13, 2020 10:16 am
Forum: 8-bit acorn software: other
Topic: Tube host ROM
Replies: 2
Views: 115

Re: Tube host ROM

Great, thanks.
by philb
Tue Oct 13, 2020 9:38 am
Forum: 8-bit acorn software: other
Topic: Tube host ROM
Replies: 2
Views: 115

Tube host ROM

Having got my B+ working I'm now thinking about adding a 2P to it. Could someone remind me which ROM(s) contain the Tube host code; is it just DNFS?
by philb
Mon Oct 12, 2020 9:27 pm
Forum: 8-bit acorn hardware
Topic: ADFS Disc Error Retries
Replies: 3
Views: 192

Re: ADFS Disc Error Retries

For floppies, it's up to ADFS to manage retries. For hard disks, I think the controller does the retries and just reports the final status back to ADFS.

To be honest, for imaging old disks (especially flaky ones) ADFS may not be the best choice. I use one of these: http://www.pdp8online.com/mfm/
by philb
Mon Oct 12, 2020 9:21 pm
Forum: 32-bit acorn hardware
Topic: eBay : A 1MB A3020 ?
Replies: 6
Views: 295

Re: eBay : A 1MB A3020 ?

It seems a bit strange that Castle would have gone to the trouble of swapping the case tops for A3020 ones in that situation. So you'd sort of expect to end up with a machine that was an A3010 in every respect other than that it had red keys.
by philb
Mon Oct 12, 2020 8:46 pm
Forum: 32-bit acorn hardware
Topic: Scanned images of Risc PC motherboards
Replies: 14
Views: 1116

Re: Scanned images of Risc PC motherboards

Interesting, I'd never actually seen a Risc PC motherboard before and I was a bit surprised by how little was on it! Obviously, thinking back rationally, there's nothing else I would have particularly expected to see there, but there's a definite disconnect between my mental image and the reality. F...
by philb
Mon Oct 12, 2020 8:00 pm
Forum: 8-bit acorn hardware
Topic: Are Rodimes Really Rubbish?
Replies: 18
Views: 538

Re: Are Rodimes Really Rubbish?

Yes, I think dedicated servo surfaces were only ever used on large disk packs (19" rack size, which might actually have included the original WInchester). Most if not all of the early 5.25" disks, at least the ones that were used with BBC systems, had stepper motor positioning and didn't use a servo...
by philb
Mon Oct 12, 2020 2:51 pm
Forum: 8-bit acorn hardware
Topic: Are Rodimes Really Rubbish?
Replies: 18
Views: 538

Re: Are Rodimes Really Rubbish?

SCSI operates purely on logical block numbers, not head/cylinder/sector numbers. I didn't think the SCSI direct-access command set even had any provision for physical geometry in it, but maybe it does (or did, at some point). Either way, I think those numbers are likely to be artificial and, as you ...
by philb
Sun Oct 11, 2020 5:54 pm
Forum: 8-bit acorn hardware
Topic: Master PSU recap
Replies: 7
Views: 232

Re: Master PSU recap

Aha, cool. Yes, there's someone selling what I assume is the right thing for £9.99. I'll get myself a pair. Thanks :-)
by philb
Sun Oct 11, 2020 3:29 pm
Forum: 8-bit acorn hardware
Topic: B+
Replies: 29
Views: 740

Re: B+

Okay, great, success. Getting the EPROM programmer working under DOSBox was fairly easy; I programmed the OS+BASIC image, put it in the B+, and I now have "Acorn OS 64K" and a BASIC prompt.

So, excellent :-) Now I just need to figure out some storage.
by philb
Sun Oct 11, 2020 1:56 pm
Forum: 8-bit acorn hardware
Topic: Master PSU recap
Replies: 7
Views: 232

Re: Master PSU recap

I cracked open one of the Masters this morning. Those PSUs don't seem to be designed to be easily dismantled: everything cable-tied to everything else! What's the trick to releasing the black grommet that the DC output wires pass through? I had thought I would be able to pull the latching part out f...
by philb
Sun Oct 11, 2020 1:51 pm
Forum: 8-bit acorn hardware
Topic: B+
Replies: 29
Views: 740

Re: B+

Just had a rummage around at the office and in a slightly unexpected stroke of good luck I found one of these:
IMG_20201011_134155.jpg
So now I just need to figure out how to get my laptop to talk to my EPROM programmer. Hopefully that will be a mere formality.
by philb
Sun Oct 11, 2020 9:57 am
Forum: 8-bit acorn hardware
Topic: Source for Econet ICs
Replies: 6
Views: 337

Re: Source for Econet ICs

Mm, right, I guess that might save a certain amount of faffing around with Mouser. If you have any of the Master modules left then I could possibly do with one or two of those as well. I'll have to conduct an inventory.
by philb
Sun Oct 11, 2020 9:21 am
Forum: 8-bit acorn hardware
Topic: Are Rodimes Really Rubbish?
Replies: 18
Views: 538

Re: Are Rodimes Really Rubbish?

RO3055 is 872 cylinders, 6 tracks, 17 sectors/track = 112 sectors/cylinder. So, if you can read the first 112 sectors OK but nothing beyond that, this would suggest that the head movement arm is stuck and it just isn't managing to seek to anything beyond track zero. I had that while imaging an old 2...
by philb
Sat Oct 10, 2020 10:31 pm
Forum: 8-bit acorn software: other
Topic: Beeb B Productivity Software
Replies: 11
Views: 285

Re: Beeb B Productivity Software

InterWord!
by philb
Sat Oct 10, 2020 9:10 pm
Forum: 8-bit acorn hardware
Topic: DFS filetype question ...
Replies: 5
Views: 137

Re: DFS filetype question ...

In general, there's no way to tell from the directory which files are BASIC vs machine code vs data. You have to "just know". As far as the addresses go, a high word of &FFFF means "load in the I/O processor" and &0000 means "load in the language processor". But BASIC files aren't really intended to...
by philb
Sat Oct 10, 2020 8:37 pm
Forum: 8-bit acorn hardware
Topic: Master PSU recap
Replies: 7
Views: 232

Master PSU recap

Apologies for what seems like it's probably an FAQ, but I couldn't immediately find the answer. Does anybody have a handy list of filter/electrolytic caps needed for a Master PSU? I don't necessarily need exact part numbers, just capacitance/voltage/case size/ESR if important. Same applies for an A5...
by philb
Sat Oct 10, 2020 7:18 pm
Forum: 8-bit acorn hardware
Topic: B+
Replies: 29
Views: 740

Re: B+

1024MAK, thanks for the audio noise notes. I think this machine is slightly worse than I remember others being, but I don't have any other working BBCs on hand right now to compare it with. (I do, however, have a large pile of machines to try...) I will have a rummage around and see if I can find a ...
by philb
Sat Oct 10, 2020 6:19 pm
Forum: 8-bit acorn hardware
Topic: Source for Econet ICs
Replies: 6
Views: 337

Source for Econet ICs

As I mentioned in the other thread I would like to fit the missing Econet parts to my B+, ideally without butchering anything else to do it. LM319s still seem to be fairly readily available, and it looks like Mouser have SN75159s in stock (in extremis I could probably fudge another line driver onto ...
by philb
Sat Oct 10, 2020 6:12 pm
Forum: 8-bit acorn hardware
Topic: B+
Replies: 29
Views: 740

Re: B+

And it has a 1770 disk interface fitted by the looks of things. I couldn't immediately spot a footprint for an 8271 on the board but I didn't look very closely. I know it's supposed to have both as options.

Edit, I just noticed the dual footprint in the photo above, doh. :-)
by philb
Sat Oct 10, 2020 5:41 pm
Forum: 8-bit acorn hardware
Topic: Are Rodimes Really Rubbish?
Replies: 18
Views: 538

Re: Are Rodimes Really Rubbish?

It might be fixable, or at least partially salvageable, but it does rather depend what's wrong. Do you have a map of which sectors are good and bad?
by philb
Sat Oct 10, 2020 5:39 pm
Forum: 8-bit acorn hardware
Topic: B+
Replies: 29
Views: 740

Re: B+

Ah excellent, thanks. I'll give that a try as soon as I can locate a blank EPROM and my programmer.
by philb
Sat Oct 10, 2020 3:54 pm
Forum: 8-bit acorn hardware
Topic: B+
Replies: 29
Views: 740

Re: B+

IMG_20201010_154704.jpg
Here it is.
by philb
Sat Oct 10, 2020 2:32 pm
Forum: 8-bit acorn hardware
Topic: Are Rodimes Really Rubbish?
Replies: 18
Views: 538

Re: Are Rodimes Really Rubbish?

My recollection is yes, Rodimes did have a reputation for poor reliability. Of course, disks of that era (I think Rodime stopped manufacturing by about 1990) were always rather fragile anyway, and I think Acorn ended up replacing Rodimes with Miniscribes which were not an obvious step up in quality ...
by philb
Sat Oct 10, 2020 12:28 pm
Forum: 8-bit acorn hardware
Topic: B+
Replies: 29
Views: 740

Re: B+

Yup, that's the puppy.
by philb
Sat Oct 10, 2020 11:55 am
Forum: 8-bit acorn hardware
Topic: B+
Replies: 29
Views: 740

Re: B+

Mm, fairly sure it's not that. My best guess at the moment is that it really is a B+ but it's had the wrong OS ROM fitted at some point for whatever reason. Might have to exhume my EPROM programmer... !
by philb
Sat Oct 10, 2020 11:49 am
Forum: 8-bit acorn hardware
Topic: B+
Replies: 29
Views: 740

Re: B+

Yeah, that's what I was wondering. It looks pretty much like I remembered a B+ being; it's got the ROM sockets at the back left and the footprint for the extra RAM header in the bottom right, so I'd jumped to the conclusion that's what it was. But I don't think I've ever seen a US or German model B ...
by philb
Sat Oct 10, 2020 11:38 am
Forum: 8-bit acorn hardware
Topic: B+
Replies: 29
Views: 740

B+

Just trying to resurrect a B+ (or at least I think it's a B+) that I've had sitting in a corner for quite some time. I've replaced the primary side capacitors in the power supply and it seems to power up fine. A few questions... The startup banner says "BBC Computer 32k" which sounds rather more lik...
by philb
Wed Oct 03, 2018 4:58 pm
Forum: other vintage hardware, software and languages
Topic: Question about linear PSUs
Replies: 12
Views: 1038

Re: Question about linear PSUs

Agreed, I don't think you want to do a full "live" test of the SCR crowbar circuit. If you do fire the crowbar then at best it will almost certainly blow a fuse, which might be irritating to replace, at worst you might end up overstressing or destroying some of the other components in the process, a...
by philb
Mon Oct 01, 2018 2:56 pm
Forum: 8-bit acorn hardware
Topic: MicroVitec CUB Flyback / LOPT Replacement
Replies: 1
Views: 381

Re: MicroVitec CUB Flyback / LOPT Replacement

What made you decide that the LOPT is bad? If it does eventually focus after it's warmed up, and there isn't any obvious arcing or other sign of HV breakdown, I don't think I would necessarily rush to suspect the LOPT. That said if you've already bought the part then I guess there's no harm in swapp...
by philb
Sat Sep 29, 2018 7:52 pm
Forum: 8-bit acorn hardware
Topic: MDFS Key Losted
Replies: 17
Views: 1686

Re: MDFS Key Losted

I'm fairly sure the Nexus keys are the same L&F series as the MDFS ones, just a different code number. If you can get someone with an original key to tell you the number (or it might even be stamped on the lock body, I forget) then you should be able to order one through the same link I posted earli...

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