Search found 61 matches

by cliffh
Sun May 13, 2018 9:51 am
Forum: hardware
Topic: Restoring an A3000 with lots of battery damage
Replies: 8
Views: 569

Re: Restoring an A3000 with lots of battery damage

Wow, do you think that battery exploded? :shock: Great clean up - it looks like a new machine. Reattaching the keyboard and putting the Delete keycap back on let me do a CMOS reset on startup... and it booted into the desktop :D Congratulations. =D> So... I tried plugging it in to the original PSU, ...
by cliffh
Fri Mar 30, 2018 8:45 am
Forum: hardware
Topic: RTFM Joystick interface
Replies: 2
Views: 406

Re: RTFM Joystick interface

I looked out the manual that came with my RTFM interface but it turned out to be a single information sheet with no technical details at all. I think it is not much use, but might have some curiosity value if you haven't already seen it:
RTFM.pdf
(187.86 KiB) Downloaded 18 times
by cliffh
Sun Apr 23, 2017 9:55 am
Forum: hardware
Topic: Repairing a broken Archimedes A3000 ... Update 14.05.17 - mouse progress - the mouse fully works too! I think, it's done
Replies: 159
Views: 7925

Re: Repairing a broken Archimedes A3000 ... Update 22.04.17 - some more questions ...

I fitted the diode (4007) on the plus cable ... like they guy on waitingforfriday and some others. That's the way I did it. I found it appealingly simple (using only a single AA cell) and I can vouch for the fact that it works - but I didn't know at the time that there are neater and safer ways of ...
by cliffh
Wed Mar 29, 2017 6:51 pm
Forum: hardware
Topic: Repairing a broken Archimedes A3000 ... Update 14.05.17 - mouse progress - the mouse fully works too! I think, it's done
Replies: 159
Views: 7925

Re: Repairing a broken Archimedes A3000 ...

Yes, i can confirm it. What does it mean? It means there are failed rows on the input side of the keyboard, and you should probably focus on the 74LS145s, the integrity of the tracks leading to and from these chips and the keyboard socket SK7. It doesn't pin down the location of the faults precisel...
by cliffh
Wed Mar 29, 2017 4:56 pm
Forum: hardware
Topic: Repairing a broken Archimedes A3000 ... Update 14.05.17 - mouse progress - the mouse fully works too! I think, it's done
Replies: 159
Views: 7925

Re: Repairing a broken Archimedes A3000 ...

That pattern of failed keys is consistent as far as it goes. There are two very useful diagrams by jms2 which colour code the keys according to their positions in the keyboard matrix. See this thread: http://www.stardot.org.uk/forums/viewtopic.php?f=16&t=6002 Find the post dated May 04, 2013 and ope...
by cliffh
Wed Mar 29, 2017 12:34 pm
Forum: hardware
Topic: Repairing a broken Archimedes A3000 ... Update 14.05.17 - mouse progress - the mouse fully works too! I think, it's done
Replies: 159
Views: 7925

Re: Repairing a broken Archimedes A3000 ...

which ICs are responsible for the keyboard and are they get faulty sometimes? The 74LS145 decoder/driver chips IC4 and IC5 generate pulses for scanning the keyboard. They are just above the battery location in your photographs and they are vulnerable to battery leakage. Failure of these chips can d...
by cliffh
Mon Aug 01, 2016 9:11 am
Forum: hardware
Topic: A3000 with keyboard problems
Replies: 10
Views: 919

Re: A3000 with keyboard problems

Most of the keys work, however a couple don't work at all, whilst quite a few produce a random character from a set, for example . produces '.', '+' and '4'. That's an interesting puzzle! It strikes me that failed connections could account for the keys that don't work at all, but not the ones that ...
by cliffh
Tue Feb 09, 2016 11:03 am
Forum: emulators
Topic: Omniflop and .adf files
Replies: 8
Views: 1907

Re: Omniflop and .adf files

Glad you found the solution. :) Just to confirm this is a common problem, here are some notes I made a few years back: Adf seems to be the most common type for distributing Archimedes software on the Internet for use with Arculator etc., but OmniFlop defines this as a single-sided (head 0) format. I...
by cliffh
Sun Oct 25, 2015 5:51 pm
Forum: hardware
Topic: A3000 on AKF30 Monitor
Replies: 18
Views: 1428

Re: A3000 on AKF30 Monitor

Perhaps I can help after all. I just recalled that I have a VGA cable in my spares box that I have never used - and it turned out to have 9 pin male and female connectors. I tested it with my Fluke then checked the connections against pinouts in the A3000 Technical Reference Manual http://chrisacorn...
by cliffh
Sat Oct 24, 2015 11:56 am
Forum: hardware
Topic: A3000 on AKF30 Monitor
Replies: 18
Views: 1428

Re: A3000 on AKF30 Monitor

Welcome to the forum Mike. So I've gone from nothing to almost everything working in no time at all. Congratulations! :D It’s great to hear about another of these classic machines being rescued. I hope the keyboard and mouse weirdness doesn’t reappear, but if it does I have a thought on one possible...
by cliffh
Sat Oct 17, 2015 5:10 pm
Forum: hardware
Topic: A3000 Connection!
Replies: 22
Views: 4354

Re: A3000 Connection!

I’ve had similarly positive experiences playing with one of these upscalers. I think the image is pretty good really, especially considering the resolution from the machines. lag - none noticeable (that I can see)... I agree. I can see a little bit of artifacting, especially around the moving mouse ...
by cliffh
Tue Oct 06, 2015 7:34 pm
Forum: hardware
Topic: Phihong Power Supply for A3000
Replies: 7
Views: 1022

Re: Phihong Power Supply for A3000

The power supply in my machine is held in place by a single plastic rivet. There is a brief description of how to remove and refit this in the service manual, but I found the job surprisingly difficult. Part of the problem is that you get a very restricted view through the small hole in the cover, s...
by cliffh
Tue Oct 06, 2015 9:35 am
Forum: hardware
Topic: Phihong Power Supply for A3000
Replies: 7
Views: 1022

Re: Phihong Power Supply for A3000

Paul and Mark Thanks for putting me right on the zero load case. I can see that the conclusion I drew initially from that was unfounded. However, the subsequent discussion does seem to have revealed a genuine problem with the spare. Either the design was changed during production to improve the regu...
by cliffh
Mon Oct 05, 2015 4:20 pm
Forum: hardware
Topic: Phihong Power Supply for A3000
Replies: 7
Views: 1022

Re: Phihong Power Supply for A3000

Thanks for the tip Mark. I have some small lightbulbs rated at 6V, 60mA which I connected in turn to bring the load up from zero to around 180mA. The results are: Original (installed) PSU: 0mA, 5.03V 40, 5.00 95, 4.98 135, 4.96 182, 4.94 800, 5.00 (running the A3000) Spare PSU: 0mA, 6.15V 40, 5.75 9...
by cliffh
Sun Oct 04, 2015 7:15 pm
Forum: hardware
Topic: Phihong Power Supply for A3000
Replies: 7
Views: 1022

Re: Phihong Power Supply for A3000

Paul Yes, I tested it off load. I also adjusted the original unit to 5V off load, and it remained at 5V when I reconnected it to the motherboard, so I was nervous about doing the same thing with the new one in case it remained at 6.3V. I will try it again on the bench under slight load and see if th...
by cliffh
Sun Oct 04, 2015 1:59 pm
Forum: hardware
Topic: Phihong Power Supply for A3000
Replies: 7
Views: 1022

Phihong Power Supply for A3000

I have a spare Phihong PSM-054 power supply that I was intending to drop into my A3000 as a replacement for a faulty unit, but when I tested it on the bench I found that its output was not 5V as it should be, but 6.3V. Phihong PSM-054.jpg There is a potentiometer on the board (top right in the pictu...
by cliffh
Mon Feb 09, 2015 9:47 am
Forum: hardware
Topic: Philips CM8833 Monitor, Sound Card Repair
Replies: 13
Views: 2456

Re: Philips CM8833 Monitor, Sound Card Repair

Fitting them is really easy as long as you know what you're doing around CRTs. (If you don't then it's probably best to ask someone who does to do the repair for you.) Good advice, and an essential point to make. I intended to tell a light hearted story, but on a serious note, there's a safety issu...
by cliffh
Sun Feb 08, 2015 4:20 pm
Forum: hardware
Topic: Philips CM8833 Monitor, Sound Card Repair
Replies: 13
Views: 2456

Re: Philips CM8833 Monitor, Sound Card Repair

DutchAcorn wrote:on second read I see that you already replaced the parts
Yes, I did manage to get the spares, but thank you for your offer of help - it's very much appreciated. :D
by cliffh
Sun Feb 08, 2015 3:59 pm
Forum: hardware
Topic: Philips CM8833 Monitor, Sound Card Repair
Replies: 13
Views: 2456

Re: Philips CM8833 Monitor, Sound Card Repair

Semiconductor based amplifiers don't normally have a problem with an open circuit speaker circuit. Thank's for this. It seems to rule out my best guess - so maybe this is going to remain a mystery. I will be extra careful next time I open the case, but I hope that will be a long time in the future!
by cliffh
Sun Feb 08, 2015 3:37 pm
Forum: hardware
Topic: Philips CM8833 Monitor, Sound Card Repair
Replies: 13
Views: 2456

Re: Philips CM8833 Monitor, Sound Card Repair

I was wondering if you could supply any more details or photos of the power-switch repair I didn't take any photographs, but the replacement switch I bought from CJE Micros is listed here: On/Off Switch for Many Philips and Acorn Monitors . I can vouch for the fact that it fits the CM8833 Mk1. The ...
by cliffh
Sun Feb 08, 2015 12:37 pm
Forum: hardware
Topic: Philips CM8833 Monitor, Sound Card Repair
Replies: 13
Views: 2456

Philips CM8833 Monitor, Sound Card Repair

I doubt the details of this repair will be of general interest, because I think the sound card is one of the least likely things to fail on the excellent but ageing CM8833 monitor, but it strikes me as interesting story of near disaster and unexplained mystery (like most of my hardware projects). He...
by cliffh
Wed Feb 04, 2015 10:49 am
Forum: software
Topic: RISC OS 3, C Application Tutorials
Replies: 18
Views: 3592

Re: RISC OS 3, C Application Tutorials

I've jumped to RISC OS 5.21 on the Raspberry Pi, so this is getting a bit off topic, but I want to share this with the folks at ROOL and can't see a way to post attachments on their forum - so have posted here in the meantime. I've been learning to use Toolbox gadgets, which I have to say are very n...
by cliffh
Mon Oct 20, 2014 8:58 am
Forum: emulators
Topic: ArcEm 1.50 released
Replies: 7
Views: 2206

Re: ArcEm 1.50 released

I haven't been following developments on RO5 on the Pi B recently, but if the USB issues have been resolved, that would be great. As far as I can tell from my limited testing they have been resolved completely, but I would be interested to hear if others have the same impression. For the record, he...
by cliffh
Sun Oct 19, 2014 5:02 pm
Forum: emulators
Topic: ArcEm 1.50 released
Replies: 7
Views: 2206

Re: ArcEm 1.50 released

I just got my Raspberry Pi B out to do some C++ programming, but I’ve been sidetracked by ArcEm for the moment. What a beautiful emulator this is! To me there is something particularly satisfying about emulating one classic ARM/RISC OS machine on another. Actually, I first had a look at this over a ...
by cliffh
Sun Oct 12, 2014 2:51 pm
Forum: software
Topic: RISC OS 3, C Application Tutorials
Replies: 18
Views: 3592

Re: RISC OS 3, C Application Tutorials

Yes, RISCOSLib is a simple wrapper around the SWIs. I suppose the main benefit of this is the ability to use the PRM or other manuals to make up for the lack of actual documentation for RISCOSLib. I never used the library myself back in the day, having instead dabbled with wrapping the SWIs myself ...
by cliffh
Tue Oct 07, 2014 12:31 pm
Forum: software
Topic: RISC OS 3, C Application Tutorials
Replies: 18
Views: 3592

Re: RISC OS 3, C Application Tutorials

Paul Apologies for my misunderstanding of your earlier post. I thought you were describing a process that would simply ignore the redraw rectangles, hence would have no basis for doing anything other than updating the whole image, which would require only a single blit and no redraw loop and would i...
by cliffh
Mon Oct 06, 2014 9:27 pm
Forum: software
Topic: RISC OS 3, C Application Tutorials
Replies: 18
Views: 3592

Re: RISC OS 3, C Application Tutorials

richardtoohey wrote:hang on, sprite_put_given() is a call in some library or other, not RISC OS itself?
It's defined in RISC_OSLib which is supplied with Desktop C. I don't know if it gets a mention in the PRMs.
by cliffh
Mon Oct 06, 2014 8:07 pm
Forum: software
Topic: RISC OS 3, C Application Tutorials
Replies: 18
Views: 3592

Re: RISC OS 3, C Application Tutorials

Thanks for your thoughts Paul. I had wondered if sprite_put_given() was bypassing the normal redraw mechanism and doing something along the lines you describe - but if it were, this would pose some more questions: If the image is blitted in one go, why is there any need for a redraw loop ? How would...
by cliffh
Mon Oct 06, 2014 9:05 am
Forum: software
Topic: RISC OS 3, C Application Tutorials
Replies: 18
Views: 3592

Re: RISC OS 3, C Application Tutorials

I had a few more thoughts on my software enquiry. I put a counter in the redraw loop so that sprite_put_given() was only called the first time round - and, sure enough, some rectangular areas are not updated when another window is dragged across the Sier window. All the indications are that sprite_p...