Search found 1789 matches

by IanS
Fri Jun 11, 2021 11:53 pm
Forum: 8-bit acorn hardware
Topic: BeebMaster Econet Clock Issue 2
Replies: 22
Views: 451

Re: BeebMaster Econet Clock Issue 2

BeebMaster wrote:
Fri Jun 11, 2021 11:32 pm
Probably a good job as I think I have put it on the wrong way wround (long lead to square pad) so when I powered it up nothing happened.
You didn't fit a switch for the PwrLED, put a wire link across the pins below the "mark" switch.

edit: or has it got JP1 linked on the back?
by IanS
Fri Jun 11, 2021 10:10 pm
Forum: 32-bit acorn hardware
Topic: A300 series 4-slot backplane
Replies: 12
Views: 214

Re: A300 series 4-slot backplane

How confident are you that the drilled holes for the power supply have made a good connection to the inner power plane (is it 4 layer?) I'm confident enough that they buzz-out. Will add some strapping to other points anyway. And disco ... that was the issue. She works now :D Good news. That's an ea...
by IanS
Fri Jun 11, 2021 8:04 pm
Forum: 32-bit acorn hardware
Topic: ARM3 upgrade for Archimedes
Replies: 9
Views: 221

Re: ARM3 upgrade for Archimedes

Excellent.

So that's backplane, ARM3, when do you announce the motherboard re-make?
by IanS
Fri Jun 11, 2021 7:59 pm
Forum: 32-bit acorn hardware
Topic: A300 series 4-slot backplane
Replies: 12
Views: 214

Re: A300 series 4-slot backplane

Not likely to be your problem at the mo, but whilst I notice. C5 shouldn't go to all podules. Also applies to C7, C8 C9, C10, C11, C31. They are mainly co-pro signals, so should only be connected to podule 2 (the one nearest the motherboard connector) If you add in row B from the motherboard to podu...
by IanS
Fri Jun 11, 2021 5:48 pm
Forum: 32-bit acorn hardware
Topic: A300 series 4-slot backplane
Replies: 12
Views: 214

Re: A300 series 4-slot backplane

Awesome, I'd had that on my list of things to do for ages, just hadn't got around to the faff of measuring where everything went.

How confident are you that the drilled holes for the power supply have made a good connection to the inner power plane (is it 4 layer?)
by IanS
Wed Jun 09, 2021 3:57 pm
Forum: 32-bit acorn hardware
Topic: A5000 - is Desktop Possible Without CMOS Battery?
Replies: 10
Views: 214

Re: A5000 - is Desktop Possible Without CMOS Battery?

Does the delete key work? Do yu see a red border during power-up, which is when the cmos should be reset. My money is on a broken cmos chip if you still can't get to the desltop with delete pressed. I don't think trying to rereinit modules with a broken cmos is a useful effort. I'm not even sure it ...
by IanS
Wed Jun 09, 2021 2:58 pm
Forum: 32-bit acorn hardware
Topic: A5000 - is Desktop Possible Without CMOS Battery?
Replies: 10
Views: 214

Re: A5000 - is Desktop Possible Without CMOS Battery?

Press delete, turn the power on, wait till the desktop appears. Don't release delete untill the desktop or the RISC OS banner appears . What happens? Do you still get floppy error codes?, if so the CMOS probably has broken tracks (battery damage) or needs replacing (or both). It is possible to get t...
by IanS
Tue Jun 08, 2021 8:40 am
Forum: 32-bit acorn hardware
Topic: RTFM Joystick interface recreations
Replies: 41
Views: 1029

Re: RTFM Joystick interface recreations

cheshirenoir wrote:
Tue Jun 08, 2021 8:32 am
I would have assumed someone would have taken this measurement already.
The econet module pins are all on a 0.1" grid, the two rows are 1.7" (43.18mm) apart.
by IanS
Mon Jun 07, 2021 11:52 am
Forum: 8-bit acorn hardware
Topic: Model A PSU
Replies: 13
Views: 328

Re: Model A PSU

Looks the same as the one that hoglet traced the schematic - viewtopic.php?p=111670#p111670
by IanS
Sun Jun 06, 2021 10:32 pm
Forum: general
Topic: Tape file info - how?
Replies: 8
Views: 236

Re: Tape file info - how?

On tape isn't that info shown when you do *CAT?
by IanS
Sun Jun 06, 2021 2:06 pm
Forum: for sale / freebies
Topic: VideoNuLA boards
Replies: 239
Views: 40400

Re: VideoNuLA boards

RobC wrote:
Sun Jun 06, 2021 1:53 pm
Unfortunately, although I ordered more PCBs a few weeks ago, they've mistakenly sent me someone else's boards!
Interesting, I had that happen with allpcb.com earlier in the year, who sent you the wrong boards?
by IanS
Fri Jun 04, 2021 10:36 pm
Forum: 32-bit acorn hardware
Topic: RTFM Joystick interface recreations
Replies: 41
Views: 1029

Re: RTFM Joystick interface recreations

So like this? (I reckon there's probably only one more version to do after this, and that'll wait until someone can confirm what pins on the connectors go to what pins on the DE9/Joystick. Once I have that I can simplify it to use IDC connectors, and then I'll turn it into a double layered PCB.) Ch...
by IanS
Thu Jun 03, 2021 10:09 pm
Forum: 32-bit acorn hardware
Topic: A3000 Repair adventure
Replies: 11
Views: 430

Re: A3000 Repair adventure

Looking good. You've done a good job of cleaning it all up.
by IanS
Thu Jun 03, 2021 9:35 pm
Forum: 32-bit acorn hardware
Topic: RTFM Joystick interface recreations
Replies: 41
Views: 1029

Re: RTFM Joystick interface recreations

The 74ls32 is an OR gate, so the output is 1 when either of the inputs is 1. But the signals are all active low, so we are interested in when the inputs are both low (0), which will cause the output to also be low, enabling the outputs from the buffers (U1 & U2 - 74ls240). So U2 is enabled by U?...
by IanS
Wed Jun 02, 2021 2:14 pm
Forum: 32-bit acorn hardware
Topic: RTFM Joystick interface recreations
Replies: 41
Views: 1029

Re: RTFM Joystick interface recreations

No idea where a lot of stuff is going yet. :-) So +5 is fed to the joystick ports (to allow for auto-fire models) on pin 6 of J2 and J1, thus giving a pull-up via the resistor arrays to the inputs. Pin7 of J1 and J2 is GND, each joystick input goes via a switch to GND. Pin 5 of J1 uses the other ha...
by IanS
Wed Jun 02, 2021 2:00 pm
Forum: 32-bit acorn hardware
Topic: RTFM Joystick interface recreations
Replies: 41
Views: 1029

Re: RTFM Joystick interface recreations

cheshirenoir wrote:
Wed Jun 02, 2021 1:47 pm
Is it me, or could an entire 74LS240N be dropped, simply by using both halves of one?
Nope, you need 5 inputs per joystick. 4 directions and fire.
by IanS
Tue Jun 01, 2021 2:41 pm
Forum: 32-bit acorn hardware
Topic: RTFM Joystick interface recreations
Replies: 41
Views: 1029

Re: RTFM Joystick interface recreations

Attached is some grotty code from the Burn 'Out support module which provided a couple of SWIs for internal use which read from RTFM joysticks and "Acorn" modules. I believe the "Econet bit" of this was just copied from some documentation/source provided by RTFM way back when. I...
by IanS
Tue Jun 01, 2021 1:50 pm
Forum: 32-bit acorn hardware
Topic: RTFM Joystick interface recreations
Replies: 41
Views: 1029

Re: RTFM Joystick interface recreations

IanJeffray wrote:
Tue Jun 01, 2021 9:20 am
Haha! I was vaguely looking in to doing exactly this after seeing one go on eBay at the weekend.
cheshirenoir wrote:
Tue Jun 01, 2021 1:44 pm
That's a much clearer photo than any I have seen. Do you have a photo without the Schematics traced in?
It's from the ebay listed shown ealier in the thread.
by IanS
Tue Jun 01, 2021 12:59 pm
Forum: 32-bit acorn hardware
Topic: RTFM Joystick interface recreations
Replies: 41
Views: 1029

Re: RTFM Joystick interface recreations

My best guess at the wiring is attached. I may bodge this together on a breadboard if someone has the software to try it with. It seems the easiest way to work out the Up/Down/Left/Right/Fire is to just try it. Looks to enable one of the 74ls240's when s<2> and an address line (la2 or la3) are both ...
by IanS
Mon May 31, 2021 4:19 pm
Forum: 32-bit acorn hardware
Topic: A5000 x4 repair Adventure
Replies: 40
Views: 1335

Re: A5000 x4 repair Adventure

Simon wrote:
Mon May 31, 2021 4:15 pm
Would anyone with a working a5000 be willing to dump a valid set of cmos settings?
The settings should be OS specific, rather than machine specific. Have you tried the A3020 dump?

(I don't own an A5000).
by IanS
Sun May 30, 2021 12:56 pm
Forum: 32-bit acorn hardware
Topic: A5000 x4 repair Adventure
Replies: 40
Views: 1335

Re: A5000 x4 repair Adventure

Keyboard activity without a keyboard connected. This is on an A3000, set to use an unconnected external keyboard. Kout is still connected to the internal controller, so you can see where a keyboard would be trying to respond to the IOC sending data. overall.PNG This shows the overall activity from p...
by IanS
Sat May 29, 2021 3:13 pm
Forum: for sale / freebies
Topic: FS: New A305/A310 4MB upgrades
Replies: 3
Views: 317

Re: FS: New A305/A310 4MB upgrades

IanJeffray wrote:
Fri May 28, 2021 9:53 pm
You're running RISC OS 3 with a MEMC1. That's interesting. For some reason, I didn't think that was possible.
It was mainly the ARM3 upgrade that forced the MEMC1a upgrade. I also think the Acorn SCSI card complained about running with a non-1a. RISC OS 3 was fine.
by IanS
Sat May 29, 2021 12:07 pm
Forum: 32-bit acorn hardware
Topic: A5000 x4 repair Adventure
Replies: 40
Views: 1335

Re: A5000 x4 repair Adventure

I stripped the keyboard down and tested the insides of it on my a3020 and it works fine (I notice they install the act/power leds even though you can't see them through the keyboard case. As you've seen the same keyboard assembly can be used in the A3000/A3010/A3020 and the external keyboard case, ...
by IanS
Wed May 26, 2021 10:21 pm
Forum: scanning of books, magazines, ads and letters
Topic: BBC Master 128 Circuit Schematics (Remastered PDF)
Replies: 15
Views: 580

Re: BBC Master 128 Circuit Schematics (Remastered PDF)

Ah, the data pins should be labelled DQ, not D0.
by IanS
Wed May 26, 2021 9:58 pm
Forum: scanning of books, magazines, ads and letters
Topic: BBC Master 128 Circuit Schematics (Remastered PDF)
Replies: 15
Views: 580

Re: BBC Master 128 Circuit Schematics (Remastered PDF)

Looks incredible, well done.

I haven't checked the original, but was curious why the A5/A6 pins are not labelled on the RAM (IC17/18/23/26). Aren't the data pins D0-D3, rather than all D0?
by IanS
Tue May 25, 2021 8:36 pm
Forum: 32-bit acorn hardware
Topic: Identifying upgrades in A420/1, troubleshooting faults
Replies: 28
Views: 674

Re: Identifying upgrades in A420/1, troubleshooting faults

Thanks Andy, I do think it's either the monitor SCART socket or the cable itself too. I've done a continuity check on the cable and got the following results: Not sure I understand your table. It looks like you are saying pin 11 on te SCART connector is connected to pins 1, 2 and 3 of the "VGA...
by IanS
Mon May 24, 2021 8:15 pm
Forum: 32-bit acorn hardware
Topic: A5000 x4 repair Adventure
Replies: 40
Views: 1335

Re: A5000 x4 repair Adventure

Ok, Sadly it all buzzes out ok, I guess that means either IC5 or IOC is busted :( IC5 seems simple enough to replace and have have 4 of these :) I really do need to get a scope, any recommendations for a cheapish but not junk one. For monitoring things like the keyboard, a logic anlyzer is probably...
by IanS
Mon May 24, 2021 4:27 pm
Forum: 32-bit acorn hardware
Topic: Identifying upgrades in A420/1, troubleshooting faults
Replies: 28
Views: 674

Re: Identifying upgrades in A420/1, troubleshooting faults

The arc output is not TTL, so probably not useful.

You can a jumper to LK5 and get a B/W composite video output from the "SYNC" BNC connector.
by IanS
Mon May 24, 2021 1:22 pm
Forum: 32-bit acorn hardware
Topic: Identifying upgrades in A420/1, troubleshooting faults
Replies: 28
Views: 674

Re: Identifying upgrades in A420/1, troubleshooting faults

I'd be tempted to leave the vidc enhancer disconnected from PL4 for testing. Though you will need to replace it with two jumpers, 1-2 & 3-4 on PL4.
by IanS
Mon May 24, 2021 11:33 am
Forum: 32-bit acorn hardware
Topic: Identifying upgrades in A420/1, troubleshooting faults
Replies: 28
Views: 674

Re: Identifying upgrades in A420/1, troubleshooting faults

I don't think that'll be a VIDC enhancer, as it's not feeding appropriate places on the board, AFAICS. Though it does look like that'll be a crystal on the left. If the board can be lifted, photograph the IC on the other side and we may have a better idea. It looks like it's just tapping the backpl...

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