Search found 2001 matches

by jms2
Thu Aug 09, 2018 7:51 pm
Forum: hardware
Topic: Slogger & Prime's MRB (Master RAM Board - Turbo)
Replies: 7
Views: 186

Re: Slogger & Prime's MRB (Master RAM Board - Turbo)

OK, I did get a moment to do a quick check. People living in the East Midlands may have noticed the lights dimming momentarily as I powered up the Plus 3 PSU... :D I may not have checked the exact configuration that you might have wanted, but this is what I did: - Electron with Plus 3 and Plus 1. - ...
by jms2
Thu Aug 09, 2018 6:08 pm
Forum: hardware
Topic: Slogger & Prime's MRB (Master RAM Board - Turbo)
Replies: 7
Views: 186

Re: Slogger & Prime's MRB (Master RAM Board - Turbo)

That looks like the kind of strange anomaly that affects my machines Dave! I'm slightly surprised that you've not had more replies, but I imagine that the user base is very small. Anyway... I have one of these boards, so I will give it a try. It's in a machine which also has a Plus 3. However I'm un...
by jms2
Wed Aug 08, 2018 5:07 pm
Forum: acorn atom
Topic: Building an Acorn System 1
Replies: 13
Views: 462

Re: Building an Acorn System 1

Congratulations! I love reading about this kind of project.
by jms2
Wed Aug 08, 2018 5:04 pm
Forum: other vintage computer hardware, software and games
Topic: C64 phase 2 of repairs
Replies: 25
Views: 596

Re: C64 destroying 5v PSUs?

Those screen-clearing functions do work, but I have not tried scrolling the screen; that's a good tip.

Unfortunately my tinkering time will now be zero for the next couple of weeks - but I'll be having fun doing other things so it's all good.
by jms2
Wed Aug 08, 2018 12:10 pm
Forum: other vintage computer hardware, software and games
Topic: C64 phase 2 of repairs
Replies: 25
Views: 596

Re: C64 destroying 5v PSUs?

That's the one I tried - it works, and does produce noise. :D Not sure why the test cartridge doesn't. This machine isn't released from hospital yet though. I have tried giving it a more thorough workout and various problems have come to light (probably all related to each other I suspect): 1) Whils...
by jms2
Wed Aug 08, 2018 9:26 am
Forum: other vintage computer hardware, software and games
Topic: C64 phase 2 of repairs
Replies: 25
Views: 596

Re: C64 destroying 5v PSUs?

Thanks... I just googled it and found the same thing. Not what I expected, but as you say the lead may well just be composite video.

I am fighting the urge to try some games... going on holiday soon so I really ought to be doing some useful jobs instead!
by jms2
Wed Aug 08, 2018 8:22 am
Forum: other vintage computer hardware, software and games
Topic: C64 phase 2 of repairs
Replies: 25
Views: 596

Re: C64 destroying 5v PSUs?

Also.. any thoughts on what is going on here? If I change the colour to red, everything goes super-blurry. Purple is the same. Other colours are not so bad.

This is using a proper C64-SCART cable with LCD TV.
P1120746.JPG
by jms2
Wed Aug 08, 2018 8:05 am
Forum: other vintage computer hardware, software and games
Topic: C64 phase 2 of repairs
Replies: 25
Views: 596

Re: C64 destroying 5v PSUs?

I tried dumping the Kernal and BASIC roms and found that they are both OK (as before). However, to get a reliable dump of BASIC I found I needed to clean the pins. Doing this caused the machine to boot! =D> P1120743.JPG It still doesn't seem 100% reliable though. Sometimes when I switch it on, I jus...
by jms2
Mon Aug 06, 2018 9:54 pm
Forum: other vintage computer hardware, software and games
Topic: C64 phase 2 of repairs
Replies: 25
Views: 596

Re: C64 destroying 5v PSUs?

Unfortunately, although I have many tape games, I don't have any cartridges. But you are right - I have not done anything with the character rom so far. Any kind of progress is rewarding though. I have had nothing but the black screen of death from this machine ever since getting it. Now the repair ...
by jms2
Mon Aug 06, 2018 6:05 pm
Forum: other vintage computer hardware, software and games
Topic: C64 phase 2 of repairs
Replies: 25
Views: 596

Re: C64 destroying 5v PSUs?

I obtained 4x new TI 4164s today. Plopping one into the vacant slot has brought the machine to life! :D The dead test cartridge runs and finds no problems. Even the SID is fine. :D However, without the cartridge the machine still gives a black screen. I'm going to dump the BASIC and Kernel roms again.
by jms2
Thu Aug 02, 2018 9:44 pm
Forum: other vintage computer hardware, software and games
Topic: C64 phase 2 of repairs
Replies: 25
Views: 596

Re: C64 destroying 5v PSUs?

Switch seems fine. And there's more good news: I have been working through the ram chips, removing the hot Samsung chips (in order of temperature) and putting back the original Hitachi chips. When I renewed U21, the flash code changed to 2x flashes - indicating a fault at U24. Swapping U24 back to H...
by jms2
Thu Aug 02, 2018 6:30 am
Forum: other vintage computer hardware, software and games
Topic: C64 phase 2 of repairs
Replies: 25
Views: 596

Re: C64 destroying 5v PSUs?

You may want to consider buying a new multimeter. Would save you from another wild goose chase... Yes, fair point! I know this one is cheap (it is branded though - Hills), but I have only ever needed it to give me indicative results. eg: is something powered or not powered, connected or not connect...
by jms2
Wed Aug 01, 2018 8:57 pm
Forum: other vintage computer hardware, software and games
Topic: C64 phase 2 of repairs
Replies: 25
Views: 596

Re: C64 destroying 5v PSUs?

The board does seem to be getting the right voltages. I'm not sure what to look for at the on/off switch though - there's no visible arcing, but is that a reliable guide?

The fact that I got different results on occasion could possibly indicate inconsistent behaviour at the switch, maybe?
by jms2
Wed Aug 01, 2018 7:09 pm
Forum: general
Topic: Best Acorn History article or book?
Replies: 2
Views: 130

Re: Best Acorn History article or book?

This is a good web page - not much detail but strong on dates. http://www.mcmordie.co.uk/acornhistory/index.shtml
by jms2
Wed Aug 01, 2018 6:53 pm
Forum: other vintage computer hardware, software and games
Topic: C64 phase 2 of repairs
Replies: 25
Views: 596

Re: C64 destroying 5v PSUs?

After a quick scan of your previous thread concerning this ... Does the breadbin switch on? LED light up? Get any form of tv signal in its current state? Yes, I can switch it on and get a red LED. Before buying the dead test cart, I got a totally black screen but latterly I was able to get multicol...
by jms2
Tue Jul 31, 2018 11:11 am
Forum: other vintage computer hardware, software and games
Topic: C64 phase 2 of repairs
Replies: 25
Views: 596

Re: C64 destroying 5v PSUs?

It's not the C64 destroying the PSU but the other way around. Thanks, but I know about this problem - I think my C64 has been affected and that's why I have tried to rig up my own supply in the form of a cheaper alternative to the Ray Carlsen solution. I got the idea from this website . I'm going t...
by jms2
Sun Jul 29, 2018 6:27 pm
Forum: other vintage computer hardware, software and games
Topic: C64 phase 2 of repairs
Replies: 25
Views: 596

Re: C64 destroying 5v PSUs?

Thanks Mark, I'll see if I can get a bulb off my dad.

I'll also try taking the SID out to see if that makes a difference to the voltages.
by jms2
Sun Jul 29, 2018 2:31 pm
Forum: other vintage computer hardware, software and games
Topic: C64 phase 2 of repairs
Replies: 25
Views: 596

C64 phase 2 of repairs

Back in 2016 and 2017, I posted about my misadventures trying to fix a breadbox C64: https://stardot.org.uk/forums/viewtopic.php?f=45&t=9452 . By the end of the thread, I had started to muse about the possibility of a dodgy power supply, which is a common issue on those machines. I found that the Co...
by jms2
Sun Jul 22, 2018 7:25 pm
Forum: off-topic
Topic: Using BBC BASIC to teach programming concepts in 2017
Replies: 93
Views: 2629

Re: Using BBC BASIC to teach programming concepts in 2017

Having just been for a short walk through town, I've got an update on the crucial subject of pedestrian crossing buttons (I'm sorry if this has got a bit off topic by the way :lol: - but it does tell us something about human/machine interaction I suppose). On the way in, I pressed the button to cros...
by jms2
Sat Jul 21, 2018 8:31 am
Forum: off-topic
Topic: Using BBC BASIC to teach programming concepts in 2017
Replies: 93
Views: 2629

Re: Using BBC BASIC to teach programming concepts in 2017

Well, in Derby quite a lot of the buttons don't seem to work properly. You have to press them several times before they light up.
by jms2
Wed Jul 18, 2018 8:43 pm
Forum: projects
Topic: Elite BeebAsm Source
Replies: 16
Views: 708

Re: Elite BeebAsm Source

Great - thanks Kees
by jms2
Wed Jul 18, 2018 10:30 am
Forum: projects
Topic: Elite BeebAsm Source
Replies: 16
Views: 708

Re: Elite BeebAsm Source

That's great, thanks.
by jms2
Wed Jul 18, 2018 8:15 am
Forum: projects
Topic: Elite BeebAsm Source
Replies: 16
Views: 708

Re: Elite BeebAsm Source

Kees, do you still have the disassembly of the Electron version that you started with? I've been trying to create my own but using your version would save me some time. I know it's not that hard to do, but my rate of progress is 100x slower than yours!
by jms2
Sat Jun 30, 2018 9:28 pm
Forum: software
Topic: Arc hangs when I try to run an application
Replies: 14
Views: 414

Re: Arc hangs when I try to run an application

Good news: I've kind of fixed it now. :D I decided there must be something nasty lurking in !System somewhere. I was sure I'd updated something about it - apparently it wasn't CLib, but the Toolbox modules were definitely in there, which wouldn't have been the case originally. I think I put them in ...
by jms2
Sat Jun 30, 2018 1:23 pm
Forum: software
Topic: Arc hangs when I try to run an application
Replies: 14
Views: 414

Re: Arc hangs when I try to run an application

Loaded Vprotect as part of desktop boot file, and also tried running Sparkplug from RAMFS. No change unfortunately.
by jms2
Fri Jun 29, 2018 10:49 pm
Forum: software
Topic: Arc hangs when I try to run an application
Replies: 14
Views: 414

Re: Arc hangs when I try to run an application

frustratingly, that didn't help at all. :( I tried various versions, but they all resulted in the machine locking up. What's more, I have discovered that v3.99 is actually a ROM module in Risc OS 3.10, so it must be ok. My recollection of softloading a newer version must have been false. CLib is the...
by jms2
Fri Jun 29, 2018 9:04 pm
Forum: software
Topic: Arc hangs when I try to run an application
Replies: 14
Views: 414

Re: Arc hangs when I try to run an application

Thanks everyone - the way that certain versions work but others don't is a bit strange!

Anyway I'll give those a try.
by jms2
Fri Jun 29, 2018 1:17 pm
Forum: software
Topic: Arc hangs when I try to run an application
Replies: 14
Views: 414

Re: Arc hangs when I try to run an application

I understood that part Jon, I just wasn't sure what the complete explanation was for the problem. However, having revisited the machine today I think I understand what has happened, and why it is causing a problem: 1) Not too long ago, I installed a piece of software which needed a newer version of ...
by jms2
Thu Jun 28, 2018 5:23 am
Forum: software
Topic: Arc hangs when I try to run an application
Replies: 14
Views: 414

Re: Arc hangs when I try to run an application

Another possibility, I wonder if you have one of ye olde RISC OS viruses, as these would affect disc based programmes and not ROM apps, and I recall often lead to crashes once they'd overwritten themselves a few times. Do you have VProtect module loaded at boot (assuming you have a hard disc?) Hmm,...
by jms2
Wed Jun 27, 2018 10:54 pm
Forum: software
Topic: Arc hangs when I try to run an application
Replies: 14
Views: 414

Re: Arc hangs when I try to run an application

Thanks! I did wonder about Clib. Assuming its the cause, what would be the underlying issue - inappropriate version? I'm not sure I understand the sequence of events you are describing.