BBC Model B
This machine is extremely badly behaved although it sounds and looks much worse than it actually is. I have had this machine since September 2002 but I have never had it working properly.
It is a great shame that this computer does not work properly as it is fitted with disc and Econet interfaces.
When you switch it on, all kinds of strange sounds including white noise is produced continually. The screen display works as normal but the keyboard is erratic. You can usually type a few letters - each producing its own sound effect - but when you let go of the keys, the keyboard locks up until BREAK is pressed.
I did get it to work once by unplugging the speaker and connecting it to my Econet and remoting it from another station. I ran quite a few software tests on it this way and could not find any problems. I even ran it as a Level 1 fileserver using an autoboot disc.
Having been unable to repair this Beeb, I have taken out the power supply for use with my Acorn 6502 Second Processor.
One day I may try again with the BBC Service Manual and a multi-meter.
On 21st August 2003, almost a year after I got it, I fixed this Beeb. I had previously tried replacing the keyboard, 6522, unplugging all the removable ICs one by one, without any luck at all.
A gentleman called Michael Foot e-mailed me all the way from New Zealand to suggest that IC32 may need replacing. This is a 74LS259. I don't know what it does but I got a new one and had a friend solder it in for me. I added a spare power supply, switched on, and to my amazement, the Beeb worked absolutely fine without any stray noises at all! It is already set up as Econet Station 129 and when I get a bit more space, it will be added to my network.
Click here to go back