Dave doing the dirty on a old Sony camcorder. 1985 model.
Video problems most likely the (in)famous Sony Cap problems, this unit is old enough to be in at the first batch of problem caps. The SM parts on the boards are glued down as the boards were wave soldered......
Delay line is there as part of the PAL colour system, where you need a reference of the last line chroma to do the addition and inversion that made PAL a superior system with regards to colour shift ( NTSC -Never Twice Same Color, though it really stood for National Television Standards Committee) on video. Initially meant for signal fade during broadcast, but it was robust enough to work well with the phase shifts on video recorders, where speed changes would result in small colour level changes rather than colour shifts.
Nice camera, i have broken many of them apart, as the parts are obscenely expensive, even by Sony standards. They were obsoleted very fast as well.
Hi8 though was a good tape system, capable later on of really good resolution, approaching broadcast quality. It used fine chrome oxides and later metal evaporated tapes and higher power write, which probably goes part way to explaining the poor video, as it is not compatible with this early version, as the subcarriers used to record the colour signals were moved up to get the improved video bandwidth needed. probably the sound would still work, though you would have lost the stereo available later.