February/March 1980, Issue 6

Page 16 of 38

We’ve mentioned memory plague before, and a recent note in the INMC newsletter gives a more consistent cure. However, whilst looking for the troubles with the Basic ROM with EPROMs in situ, a remarkably naughty bit of tracking on the earth line of the EPROM block was discovered. The earth track is connected to the ground plane close to pin 12 of IC27, but nowhere else!!! So I now suggest when gridding the back of the pcb that pin 12 of ICs 28, 29 and 30 be incorporated in the grid thereby Incorporating the EPROM sockets firmly into the ground plane. It can’t do any harm, and seems to do some good (but difficult to prove).

By this time the back of the memory board is beginning to look like the classic ‘rats nest’ with bits of wire and resistors hooked all over it. Don’t worry, finding the cures, and incorporating the mods was fun wasn’t It? And after all, the thing works reliably (or should anyway).

This is an OCR’d version of the scanned page and likely contains recognition errors.

Page 16 of 38