I was working on a Korg Polysix keyboard today and was pleasantly surprised at the effort that was put into making the PCBs easy to debug. In addition to little loop testpoints you can hook a scope probe onto, and labeling sections of the board with respective functions, they had labeled everything from the top panel, which was only visible from the bottom, solder side, with a second silkscreen showing the component symbols and part designators- no need to take the board out, and constantly flip it over to try to figure out which pad went to which component. Just a nice little throwback from the era of things built with repair in mind.
(https://i.postimg.cc/WFGBpRxb/0-D89063-B-4-FB8-4-F08-A2-A9-B3-C93299-C320.jpg) (https://postimg.cc/WFGBpRxb)
(https://i.postimg.cc/pyBwgHDs/2-EC0-EA3-B-EB13-40-FE-9287-AF305-EE359-EC.jpg) (https://postimg.cc/pyBwgHDs)
Also liked meaningful labels on the pins on the headers.
The trouble with the Korg Polysix is that it *needs* to be easy to repair because it's one of the most unreliable synths out there!!
But yeah, I agree - it *is* very nice to have things clearly labelled and useful test points and connections provided.