Tips On Computer Problems

By Gus Donnachaidh

Originally published in EUG #22

I have had a little experience over the years doing fairly simple repairs and post-mortems on computers. I can't claim to be an expert but I can pass on some of the experience I have gained about what tends to go wrong, why and perhaps some suggestions on what to do about it.

I can't claim to have all the answers and sure as fate I won't have the answer to your particular problem.

Now I am going to start by saying that the Elk is one of the most reliable computers around. OK, so I like it and would say that!

The sort of problems that do affect computers, in order, are:-

  1. dirty, corroded or lose contacts. Really this is way up on top of a list and is by far the most common problem;
  2. mechanical wear, power sockets, input and output sockets for monitors, drives and keyboards;
  3. poor solder joints often during manufacture but sometimes resulting from extensions and repairs;
  4. consequential damage to the electronic components as a result of one of the above;
  5. breakdown of an electronic component. In order these tend to be:
    1. capacitors,
    2. resistors,
    3. transistors,
    4. integrated circuits or chips,
    5. ROMs and ULAs.

I have written the above because so many people simply assume that the problem is electronic. With the Master 128 and BBC, there were a few design problems and consequently some of the internal components tended to have a short life. With PCs and most other modern computers, there are a multitude of design problems. With the Elk, this doesn't seem to be the case. Though sadly the same cannot be said for all the addons used by the Elk.

Before you start any work, make a drawing of the area you are working on and carefully note the positions of any wires and components you may work on. Also note which way round components go. Look for anything that appears loose, blackened or discoloured.

Cleaning contacts. A number of methods are used by different people from erasers to dabbing with a cloth soaked with meths. Really the only proper and effective way is to use a good quality aerosol cleaner such as Electronic Cleaning Solvent from Maplin Electronics (Code FC01B - £4.65) or Contact Cleaner Lubricant (Code DM85G - £4.30).

Mechanical wear will usually mean replacing the offending plug or socket. If you know someone who can do the repair, try to find the replacement component. Again, Maplin is probably a good source.

I had some trouble with a printer a while back. When using a word processor, it would only print random characters but strangely, this wasn't the case when printing directly from BASIC with VDU2. The problem was cured by removing the printer plug at both ends and then replacing.

Another problem I have had more than once are the cartridge slots on my Acorn Plus 1 losing their 'spring' through being worn. Here I simply had to chop out the old slot, de-solder the pins, clean the holes and fit a new slot from (Yes, you guessed it!) Maplin. This is not for the faint-hearted and requires some skill with a soldering iron.

When keyboards wear out and some keys won't work, it may the connector between the keyboard and the main computer board or the key itself. I have never found a way of cleaning keys that worked. JAFA may be able to help. Or you could do as Derek Walker did and build a new keyboard. Probably not such a bad idea.

Locking up happens to virtually all computers from time to time. Make a mental note of when it happens. In particular note whether it occurs with similar type of software and if you are using some addon, try removing it and using the computer for a while longer. You may need to be a little drastic here. E.g. if it's your disk drive, you will need to test the Elk by loading tape software. But if it seems to be access to a particular ROM causing the problem, try removing the ROM to another socket (If you have one). If it's in a cartridge holding two ROMs, just swap the ROMs around.

Drives do wear out. I recently bought a brand new high density 3.5" drive to replace my medium density one. It works perfectly with the Elk and only cost £30.

Poor joints can sometimes be difficult to spot even for those with experience. Look anyway. Where wires are soldered onto the board, look carefully! The Slogger Rombox+, among others, can produce a lock up problem. Sometimes a wire may need to be completely replaced. Remember to check and note its position. If you find a loose wire, look for signs of bits of strands on a nearby board. Generally, if a wire is stretched to its full length, its original position will be somewhere near to the end. This isn't a golden rule though.

Consequential damage is a bigger problem and solving it bigger still. Use a logic pulser and probe is the best advice I can give.

Breakdown of electronic components is also a problem. Sometimes the solution is obvious when you examine the circuit diagram. Sometimes not.

Some people might disagree with this article (Or some of it!) and I am open to criticism. However, never jump to any snap conclusions when trying to find a fault. Suspect the obvious first - poor contacts either through dirt or wear or corrosion.

A final piece of advice is if you ever see an Elk and/or Acorn Plus 1 and/or Acorn Plus 3 going at a reasonable price, but it! The Elk is worth having if for no other reason than to continue your EUG membership. I'm not joking. You might try another more modern computer but you will soon become disillusioned when you realise the price of the software and its poor reliability. A PC costing upwards of £1,000 new is designed only to last five years? The Elk is still going strong up to thirteen years after production. Not bad, really.

Gus Donnachaidh, EUG #22