Memory wobbles

MUCH has been written on the subject of RAM pack wobble, little of it giving any sound advice as to how it may be prevented. I feel that the three solutions which I have found are the best to date.

The Sinclair RAM would be as good as any other, except for the fact that it does not appear to be very eager to stay on the computer and will jump off when any key is touched hard enough.

If you have £2 to spare, you can buy a ribbon cable and solder one end to the RAM and plug the other to the edge connector of the PCB. That means that when you hit a key too hard, all that happens is that the ribbon cable absorbs the shock.

The second method is simpler and cheaper and just as effective. All that you do is to take a piece of Blutack and place it on the RAM, above the edge connector. When you plug in the RAM it is held to the computer by the Blutack.

The third way to stop RAM wobble, however, does not concern the Sinclair RAM but the Bug Byte RAM. Initially there is nothing wrong with the RAM and it is a very good alternative to the Sinclair RAM but the case is about three times the size it should be and so it pulls the connections apart. The answer is simple - just remove the case.

Giles Colbourne

Stopping whiteouts

I WAS very interested in your article on the ZX-81 16K RAM pack, in particular the part which stated that the computer can suffer from whiteouts due to the fluctuations in the mains supply.

I have found that to be an annoying problem, especially when loading a program which takes more than four minutes to run.

I have heard that is due to the voltage spikes in the grid over-loading the memory and resetting it to the input mode, leaving the mode K on my screen, which has happened to me.

I know that this is the problem, as the same tape and equipment will record perfectly during the times when the grid system is not being used a great deal; i.e., before 8.30am and between 2 pm and 4.30 pm. It is not always convenient or possible to work on my computer at those times; mostly I like to work in the evenings, which can be the worst time for the problem.

I know that you can obtain a filter unit which goes between the wall socket and the computer plug which will suppress the spikes but I do not know which type would be best for my ZX-81.

Could you advise me as to which method of solving the problem you would suggest and where the goods can be obtained?

Paul Coker

Can readers help? We are sending it to our Helpline correspondent, Andrew Hewson, to see if he knows the answer.

Apple threat

I AM very grateful for the April issue of Sinclair User but it does not tell me how to make my printer work. The books which are sold do not tell you, either. It would be much better if you told people how a ZX-81 works, otherwise I shall have to sell mine and buy an Apple.

I write and write again to Sinclair, without even an acknowledgment.

Maurice Nadin

We hope later issues have been more help and that you have not been compelled to take the drastic step of buying an Apple.

Changing to machine code

CONGRATULATIONS on an excellent magazine. It is just what ZX users wanted. I am not a programmer and prior to buying my ZX I did not have a clue. Through practice, I am rapidly picking up the techniques and find the hobby very interesting. I find, having bought some programs written in machine code, that they are eminently superior to anything I have written, or purchased, written in Basic. To you, that may be an obvious statement but it has become clear to me only on running them.

What I would like to do is to understand machine code - of which I now understand the basic principles - and, if possible, to buy a program which could convert some of my many Basic programs into machine code. Is that possible?

From your advertisements there are one or two firms offering products which look as if they may answer the problem - Control Technology, Bug Byte, to name two - but they do not give sufficient detail for me to decide.

I am told that what I am really looking for is a Compiler but I have not yet seen anything advertised as such. Does one exist? Can you recommend any good books or a contact with whom to discuss the matter?

D Wall

Do readers have any advice? Meanwhile, we have passed the query to Andrew Hewson, our Helpline correspondent.