To pick up on Colin Jacobs’ point.

Back in the 70’s, I built my first computer from a kit of some 50 plus IC’s, which were to be soldered onto a large mother board. The retail outlet who sold the kit, had a standing offer of $25 to fix any problem (within reason), should the kit fail to work.

Perhaps not trusting my own soldering ability or that I preferred a neater solution, I elected to solder IC sockets to the mother board, and then to plug the relevant IC’s into their respective positions. Unless I bent a contact pin during this latter step, I was fairly confident that none of the IC’s would become damaged or were over heated.

As I progressed through successive stages of the build, it was possible (using a CRO) to check the waveforms being generated. It was only during the final stages of the build that it became clear, something was not right.

Also, having built most of my brass skeleton clock by the time I started on this computer kit, I was heavily into using a 4″ binocular magnifier. It was through my new-found `hawk-eye’ ability that I noticed a tiny gap in a single copper track. Although almost invisible to the naked eye, to say that the gap was conveniently placed for anyone to bridge it with a dab of solder would be an understatement.

$25 Hmmmm?

Edited By Sam Stones on 27/04/2011 07:40:00