Last weekend’s Fixathon as a great success. Thanks to all who came, and also to those who wanted to come but couldn’t due to Covid!
Here’s work in progress. It looks like chaos, but in a nice way!
A good number of BBCs have been repaired and restored, allowing us to increase the number Econet fitted machines on display in the classroom. We’ve also arrested the worrying failure rate of the Cubs, so now every computer has a working monitor with spares available too. It’s a great culmination of work done at this and the last two Fixathons. Here's a monitor PCB undergoing treatment in the library.
What’s wrong with this one then?
Quite a few power supplies were attended to – our Master 512 was refusing to start up, getting as far as clicking its cassette relay and then loosing power. We had previously changed C9, so we suspected the high voltage capacitors C6 and C8. We changed all of the electrolytics and success!
We had a Master that would intermittently loose its screen origin when in a graphics mode. Bottom left would suddenly jump to the middle of the screen. Changing mode or pressing break would return it to normal. So we decided the 6845 was the culprit. First job was to socket the IC. We tried a 6845 for a Beeb with trepidation, as the Master uses CMOS chips. It did work – but not in mode 7! Shopping list: 68C45 to obtain.
Our Econet will now have 13 machines attached to it. We’ve also set it up as two segments linked by a bridge, with the Archimedes machines on their own segment. We’ve also made a start in linking it to another room by purloining an unused ethernet cable in the building.
This Beeb had been intermittent for some time on the Econet. We found many machines had Econet upgrades with poor soldering. Once this one was reflowed, normal service was resumed. We had another interesting Econet fault that I have put up elsewhere on Stardot.
We were lucky to have some Archimedes specialists attend the event, and this means the A4000 has had some restoration work done, now with a working disc drive. Here is the A4000 board having some capacitors changed. Our A3000 has now joined the Econet network too.
In all, a great event. I was knackered by the end of it, but I’m looking forward to arranging another one soon!
Tom
