Sometimes when you etch your own PCBs using resist ink you can have issues such as over or under etching the board. But I hadn't expected that my failure to clean and seal the board properly after soldering wuld result in oxidation eating the board away over the course of a year until my most complex hand-etched board would fail, taking my favorite and most used / enjoyed project with it.
This board was removed from the Prototype Audio Controller one year after being built. This photo was taken after the board was removed due to a ground plane problem, so some items have been removed from the board during testing. The unit had four stereo inputs, selectable by an LM1037N audio switcher chip, which is, of course, no longer in production. That chip is shown top-left, with eight capacitors and eight resistors mounted around it. It also had a tape monitor circuit, incorporated using two PC-mount 5VDC relays (removed from bottom-right) and two audio op-amps, shown top-right in the picture. The chip on the bottom was used for generating the signals to select the active input, and to display which input was selected on the front panel.
This is just a photo of the bottom, for those that wish to see my crappy hand-drawn artwork! Yes, back in the day I actually hand-drew my boards using the kits from Radio Shack.