1st April 1995Thank you for your comments about my computer letter repeating problem. I have also had a letter from Tom Boustead about using *FX commands. For the possible benefit of other readers, I will outline the results of my trials:
*FX11,0 will stop the problem but makes copying program lines more tedious (This I have to do when I'm adding DATA to my financial files). *FX11,100 or even *FX11,150 eases the problem a lot but does not stop the letter dulication completely. However, this latter is now history for my main computer has now "gone bananas". As soon as I switch on, I get RESTORE plastered on the screen up to the maximum for a line - all a CTRL-BREAK does is to clear the screen for the process to be repeated.
Sometimes this will go on to the extent thtat the computer is unusable and sometimes after up to ten minutes it reverts to normal use. Sometimes I have managed to clear the problem by powering off, detaching the computer from the Rombox+ and AP2, reassembling and switching on again. Even then I sometimes get the odd RESTORE coming in when typing something else. Sometimes I get other command words, mainly ELSE and LOCAL - all with no input from me! Any significance that these are adjacent keys?
This leads on (and maybe the problems are connected) to a telephone call I received from Ray Thomas about the suspected problem with the Pegasus 400 disk interface. He told me that he had replaced his with an AP4, which has gold-plated contacts the same as Acorn products. All Slogger's contacts are the silvered printed circuit type. Presumably these will tarnish with time and wear more easily. This is the reason I do not like to take addons on and off frequently.
Recently I had the opportunity to buy another 64K Electron with a single 5.25" disk drive and fitted with the AP4, Jafa ROMPLUS-144, Plus 1 and the Mode 7 Simulator ROM together with other software, etc. So I have taken my original Electron temporarily out of service and have coupled my 64K Electron with Jafa's Mode 7 Display Unit (mentioned when I outlined my setup in an earlier letter) to the Rombox+ through the AP2 and with the AP4 interface in place of the Pegasus 400 interface. I'm typing this letter with this setup but I'm still getting the occasional character repeating with the default *FX setting - so the fault is not just in the computer itself perhaps.
As I'm getting a little concerned with the 'safety' of my financial databank (which goes all the way back to 1983 and in some graphs to 1981!), I have also invested in a BBC B as further backup and also as a continuation of my hobby to expand the latter with the 6502 and Z80 second. Processors and 512 and the APTL Romboard - not all at the same time of course! I also intend to link my original Electron (when sorted out) and the BBC B to the monitor through one of Derek Walker's (Yes, I'm still alive, Derek!) RGB switches, the same as the two Electrons I have on line now.
Perhaps Derek can devise a switchable 7 Din connector for the back of the monitor. I have not asked him yet. I have obtained lots of other items recently and am sorting out how I'm going to link them into one overall system. What I am aiming at is differing addon setups to avoid pulling these apart for different uses as I'm sure this is not a good electronics practice.
More of this saga in the next letter. Thanks to Tom Boustead and Ray Thomas through EUG.
Tony Boarer
The problem of contacts becoming corroded is a relatively common and well-documented one. As I suggested to Allen Eccles, you could try moving any chips which are in sockets gently up and down. Contact cleaner is also available and is very good. For your chip sockets and other electronics, try to find a low residue cleaner. Maplin sell one. And, come to think of it, WD40 is just as good for the edge connectors but keep it, and other cleaners away from your keyboard at all costs: Nylon becomes sticky when exposed to any sort of lubricant including so-called switch cleaners. I have a keyboard which, while it works, requires an uncomfortable effort to press any keys.
Without wishing to contradict your logic, removing and replacing your addons may be just the thing to get rid of any tarnishing. It's really just a coating of oxidized metal. The main problem with all electronics, be it a TV remote control or a multi-million mainframe, is the exposure to air. Avoid damp or dusty environments (This is why those research labs have such stringent cleanliness). Disks are especially vulnerable. If damp does occur then allow everything to dry at room temperature for a few days.
Gus Donnachaidh, EUG #19
