"Retro Repair" key electronics skills?

While it's an understandable point of view, especially for a coder, not all ICs are digital logic - and even for those that are, understanding non-digital-logic aspects of them can be useful. (I built an EPROM reader out of SSI TTL, and found it always read the last octet as FF even in cases where I knew better. Turned out I forgot to connect the ground pin on the EPROM to circuit power ground; provided at least one input was low, it powered the chip through the input protection diodes, but when all connected pins were high - and all the non-address inputs that weren't high were tied to the ground pin - then all outputs perforce were too. But that failure mode would have been inexplicable if my mental model of the thing had been an ideal logic device.) /~\ The ASCII Mouse \ / Ribbon Campaign X Against HTML mouse at rodents-montreal.org / \ Email! 7D C8 61 52 5D E7 2D 39 4E F1 31 3E E8 B3 27 4B