Search found 458 matches

by IanS
Sat Dec 31, 2016 3:51 pm
Forum: general
Topic: Today I received.....
Replies: 4202
Views: 223517

Re: Today I received.....

Simple Econet socket box PCBs, daiy-chainable using RJ-45 network cables (should be "Phil Blundell" compatible) IMG_20161231_153858383.jpg I made it a bit too small, had to trim a bit off the 5-pin din sockets. IMG_20161231_153329777.jpg It can also have terminator components fitted on the...
by IanS
Thu Dec 29, 2016 11:47 am
Forum: other vintage computer hardware, software and games
Topic: Z80 I/O oddity on a PCW8256
Replies: 30
Views: 1027

Re: Z80 I/O oddity on a PCW8256

There are many ways of interfacing to the Z80, dpending on what you need to connect to. e.g. the CPS8256 Serial/Parallel I/F - http://www.z80.eu/pcw/cps8256circuit.gif has two methods. The Z80 DART is from the Z80 family, so just needs the /RD and /IORQ, and the /CE is decoded from the lower 8 bits ...
by IanS
Thu Dec 29, 2016 11:09 am
Forum: other vintage computer hardware, software and games
Topic: Z80 I/O oddity on a PCW8256
Replies: 30
Views: 1027

Re: Z80 I/O oddity on a PCW8256

jonb wrote:I wanted general suggestions...

I generally suggest you post the circuit, so we can see what you are talking about.

You also said you had to modify the trs-80 version , so it's no longer the same "known working" circuit.
by IanS
Wed Dec 28, 2016 7:28 pm
Forum: other vintage computer hardware, software and games
Topic: Z80 I/O oddity on a PCW8256
Replies: 30
Views: 1027

Re: Z80 I/O oddity on a PCW8256

So you want us to help debug a circuit we can't see from a vague description. I think most people will need a bit more than that to help. (You didn't get a lot of suggestions on the cpc forum, which is why I guess you are posting here)
by IanS
Wed Dec 28, 2016 6:14 pm
Forum: other vintage computer hardware, software and games
Topic: Z80 I/O oddity on a PCW8256
Replies: 30
Views: 1027

Re: Z80 I/O oddity on a PCW8256

Can you post pictures of the circuit you built (and possibly pictures of the actual build). Maybe someone can spot somthing wrong.
by IanS
Wed Dec 28, 2016 2:05 pm
Forum: hardware
Topic: Econet Bridge Circuit Diagram
Replies: 2
Views: 382

Re: Econet Bridge Circuit Diagram

I've updated the file in the first post, it should now be complete.
by IanS
Wed Dec 28, 2016 12:15 am
Forum: projects
Topic: Screenshot accessory for Arthur desktop
Replies: 4
Views: 451

Re: Screenshot accessory for Arthur desktop

Interesting, I'll give this a try when I next have my switchable OS machine out.
by IanS
Mon Dec 26, 2016 9:50 pm
Forum: hardware
Topic: Econet Bridge Circuit Diagram
Replies: 2
Views: 382

Econet Bridge Circuit Diagram

It's not complete, it needs checking and I need to update the component references for some of the passives. The chip numbers should be correct (IC? on the PCB have become U? in the PDF) Have I been wasting my time, does this already exist somewhere? I think this is now complete. Intere...
by IanS
Sat Dec 24, 2016 1:11 pm
Forum: hardware
Topic: Econet pinout
Replies: 9
Views: 552

Re: Econet pinout

Ultimately it comes down to how the hardware is configured. With an Acorn econet master module connected to an SJ Research clock the clock input to the ADLC matches the signal on pin 5 on the Din plug. I take this to be the Clock+ signal. The E01 Acorn Filestore (in-)famously got the clock signal th...
by IanS
Sat Dec 24, 2016 11:39 am
Forum: for sale / freebies
Topic: Offered: Matchbox sized 6502 / Z80 / 6809 Co Pro
Replies: 595
Views: 44676

Re: Offered: Matchbox sized 6502 / Z80 / 6809 Co Pro

Be nice if the T&C's weren't a placeholder ("Lorem ipsum dolor") http://www.xeropage.co.uk/shop/index.ph ... ent_only=1
by IanS
Fri Dec 23, 2016 1:44 pm
Forum: hardware
Topic: Super-simple Econet Clock design
Replies: 13
Views: 1181

Re: Super-simple Econet Clock design

After gathering some feedback on the original clock, I've now made a revised version which is a little more complex, but allows you to choose your clock configuration from a DIP switch (as well as some other nice additional features). The project write up is available here: http://www.waitingforfri...
by IanS
Thu Dec 22, 2016 10:42 pm
Forum: hardware
Topic: Econet pinout
Replies: 9
Views: 552

Econet pinout

According to the Econet Installation guide (and wikipedia) the 5-pin Din pinout is - 1 Data+ 4 Data- 2 Ground 5 Clock- *wrong* 3 Clock+ *wrong* http://chrisacorns.computinghistory.org.uk/docs/Acorn/Manuals/Acorn_Econet_Installation_Guide_88.pdf (page 14) https://en.wikipedia.org/wiki/Econet 5-pin di...
by IanS
Thu Dec 22, 2016 10:38 pm
Forum: general
Topic: Death-dapters - Why you really don't want them...
Replies: 42
Views: 2307

Re: Death-dapters - Why you really don't want them...

lazarusr wrote:UzgIgP0.jpg

Wow, that's a bit special. How long has it been like that? The missing cord grip really puts it in a class of its own.
by IanS
Sun Dec 18, 2016 9:05 pm
Forum: hardware
Topic: WE 32K RAM Card Repair
Replies: 37
Views: 1266

Re: WE 32K RAM Card Repair

Impressive job, Dave obviously taught you well in the art of desoldering.

I'm astounded that you managed to re-use all the old chips.
by IanS
Sun Dec 18, 2016 12:04 am
Forum: hardware
Topic: IFEL A3xx Ram upgrade chips
Replies: 3
Views: 236

Re: IFEL A3xx Ram upgrade chips

Is your board removable, or soldered on place? It looks like it attaches to the same places as many other A3xx memory upgrades - e.g. Simtec - http://www.simtec.co.uk/products/AU4M310/files/fitting.pdf But instead of lifting the resistors off the motherboard to pick up the data bus, it has pins tha...
by IanS
Sat Dec 17, 2016 8:28 pm
Forum: hardware
Topic: IFEL A3xx Ram upgrade chips
Replies: 3
Views: 236

IFEL A3xx Ram upgrade chips

Can anyone suggest a source of Memory chips for the IFEL board in my A305.
It looks like it just needs another 4 chips to push it from 2MB to 4MB.

The overall design looks more complicated than the average A3xx memory upgrade with buffers and GALs.
by IanS
Sat Dec 17, 2016 8:22 pm
Forum: hardware
Topic: Archimedes Test ROMs
Replies: 26
Views: 1163

Re: Archimedes Test ROMs

It's not pretty, but it works and it just plugs in, so it is reversable.
by IanS
Thu Dec 15, 2016 11:29 pm
Forum: hardware
Topic: Archimedes Test ROMs
Replies: 26
Views: 1163

Re: Archimedes Test ROMs

It lives!!! Great news, now you get to enjoy the long forgotten Archimedes operating system :) So with 4 times the space needed for Arthur in those flash chips, I should be able to make it switchable between 4 512K OS's. I'd say Arthur 0.3, Arthur 1.2, RISC OS 2 and some test ROMs? A good choice, I...
by IanS
Wed Dec 14, 2016 8:35 pm
Forum: hardware
Topic: Archimedes Test ROMs
Replies: 26
Views: 1163

Re: Archimedes Test ROMs

It lives!!! IMG_20161214_202227181.jpg IMG_20161214_202213916.jpg So that's an A305, original MEMC, 2MB Ram, Arthur 1.20 (from 4corn) My Arc doesn't currently have any batteries, so I was holding delete to do a CMOS reset. Don't do that, Arthur doesn't boot. Hold R, or nothing. So with 4 times the s...
by IanS
Tue Dec 13, 2016 11:53 pm
Forum: hardware
Topic: Archimedes Test ROMs
Replies: 26
Views: 1163

Re: Archimedes Test ROMs

At the moment I think I'm more concerned that the file I have isn't exactly 512K, if anyone has another image, can they post it somewhere?

Edit: There is a 512K image on 4corn - http://www.4corn.co.uk/archimedes.php

I'll try that tomorrow.
by IanS
Tue Dec 13, 2016 8:56 pm
Forum: hardware
Topic: Archimedes Test ROMs
Replies: 26
Views: 1163

Re: Archimedes Test ROMs

This is probably irrelevant, but I'll mention it anyway... One other funny thing I ran into with Arthur 0.30 is that it'll wait forever for an Econet clock, if the module is fitted. They fixed that for Arthur 1.20. It doesn't even intialise the video display, so I think it's just not working. As it...
by IanS
Tue Dec 13, 2016 8:27 pm
Forum: hardware
Topic: Archimedes Test ROMs
Replies: 26
Views: 1163

Re: Archimedes Test ROMs

Arthur is very fussy. 0.3 won't even boot if you have more than 1mb RAM, so it wouldn't be surprising if 1.2 would only run on a fairly basic machine. Arthur certainly doesn't know about ARM 3, so won't enable the cache. Possibly the MEMC1a required for ARM3 could be the problem? I tried putting Ar...
by IanS
Tue Dec 13, 2016 12:48 pm
Forum: hardware
Topic: Archimedes Test ROMs
Replies: 26
Views: 1163

Re: Archimedes Test ROMs

Is the ARM3 a problem?, I guess I should try RISC OS 2.00. ARM3 support was added in RISC OS 2.01, but I am fairly sure that this was only "detect and switch on cache", so 2.00 would also work, but with cache disabled (and hence even a bit slower than an ARM2). Yes, I tried 2.00 in 4Mb fl...
by IanS
Tue Dec 13, 2016 11:57 am
Forum: hardware
Topic: Archimedes Test ROMs
Replies: 26
Views: 1163

Re: Archimedes Test ROMs

So to slightly hijack this thread. Has anyone tried the available rom dumps on real hardware. I've got a copy of the "virtually free" roms - http://www.riscos.com/shop/products/101/index.htm I've programmed the data (de-interleaved) into 4 flash chips (28sf040). I can get 3.11 3.10 and RIS...
by IanS
Mon Dec 12, 2016 3:24 pm
Forum: hardware
Topic: Here's a thought: ARA for the Archie?
Replies: 16
Views: 780

Re: Here's a thought: ARA for the Archie?

I think Computer Concepts built such a podule, available in the early days (maybe 1st year) of the Archies. EDIT : Bingo : http://chrisacorns.computinghistory.org.uk/32bit_UpgradesA2G/CC_ROMRAM.html Don't know how easy it would be to duplicate ... (and if sbdy owns one. It's not in my collection, u...
by IanS
Sat Dec 10, 2016 9:48 pm
Forum: hardware
Topic: BBC B: replacing PSU capacitors, general questions
Replies: 18
Views: 761

Re: Issue 7 BBC B: Power cables soldered to the board

Tug hard, they are spade connectors, there is a bit soldered to the board and a crimped bit on the end of the wire, they are just a friction fit.
by IanS
Tue Dec 06, 2016 7:15 pm
Forum: general
Topic: Today I received.....
Replies: 4202
Views: 223517

Re: Today I received.....

steve3000 wrote:Just need to find some early Arthur 0.2 ROMs to make a very retro Archimedes now.

0.30 is easily available (http://www.riscos.com/shop/products/101/index.htm)

Was 0.20 ever distributed? (I started at an A3000, so only just remember the RISC OS 2 to 3 transition)
by IanS
Tue Dec 06, 2016 10:36 am
Forum: hardware
Topic: White noise and PCB flux cleaner.
Replies: 38
Views: 1418

Re: White noise and PCB flux cleaner.

flynnjs wrote:Martin, nice addition to my various other "cleaned up" schecmatics. Did you do that?
Do you know if is it raster only, or is it in vector or CAD format?

Looks to be the one listed here - http://8bs.com/insides.htm as "A redrawn diagram by J.Tribbeck."
by IanS
Mon Dec 05, 2016 5:06 pm
Forum: hardware
Topic: Archimedes Test ROMs
Replies: 26
Views: 1163

Re: Archimedes Test ROMs

I have some test roms that I got from Uniqueway along with a A3/4xx TRM on ebay many years ago. I've never tried them. I was surprised to find that they are interleaved, considering that other 4 ROM dumps of RISC OS are not interleaved. The files are exact dumps of the Eproms from the picture. I'd ...
by IanS
Mon Dec 05, 2016 1:39 pm
Forum: hardware
Topic: Archimedes Test ROMs
Replies: 26
Views: 1163

Re: Archimedes Test ROMs

Pernod wrote:Does anyone have the Test ROMs that are referenced in the A300 service manual? The ROMs replace Arthur to carry out memory tests.

I have some test roms that I got from Uniqueway along with a A3/4xx TRM on ebay many years ago. I've never tried them.
IMG_20161205_124337209_HDR.jpg

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