J.C.Wren wrote:
Phil,
Most likely the board was designed for low cost. If there is no
soldermask, larger annular rings increase the chance of solder bridges
during manufacturing. But more likely, smaller annular rings were used to
reduce the amount of solder needed, thus lowering the cost. I don't believe
they Ace nor the ZX81 nor any of that genre of computers was designed to be
repaired. They were designed to be produced as cheaply as possible.
Or any computers made since then! Cheap Cheap Cheap.!