Sequential Multitrak - Tracing leading to nowhere on board

Midi In isn’t working on my multitrak - this trace starts from the area of the Optoisolator (Midi In uses it) and seems leading to nowhere - why? The Midi In is on the right - note the tracing stops inside the white rectangle (Midi Out).
I haven’t spotted any other tracing ending in this way on this board - but there is plenty of corrections and addition (probably from the manufacturer).

if its a multi layer circuit board the tracings will disappear somewhere in between layers where you can’t trace them. Virtually all computer motherboards are like this.

You need a schematic to follow the signal path or else your just probing blind.


Well, thanks a lot for your expert feedback…you can tell I’m not that familiar with circuit boards.
Then the Midi In problem was as simple as a wrong connection between the socket and the cable. I did check the socket and seemed fine - it is one of those dins which are installed perpendicularly and prone to frontal stress. What caused the problem was the weary socket and it’s internal prongs out of place and the midi cable with very pointed pins (better midi plugs have rounded pins to ensure better contact). It was a question of microns but after a bit of fiddling inside the socket the connection is fine now.