Hey guys, I just finished refurbishing an OEM head unit from an 80s Honda Accord, I'm not sure exactly which Hondas had which stereo, but the connector should be the same as any 3rd gen Accord and I'm sure others. I personally really don't like the newer, more glamorous head units and I do like the stock look, so I keep the original unit when I can.
I'm not electrical engineer, what I fixed in this unit is the two things guaranteed to go out with age or miles, the three belts in the cassette deck, which is required for easy aux-in, and the crackling in the knobs. The build quality is excellent from a repair standpoint, butter than the Delco or Toyota units I have. The volume knob is reasonably easy to repair, but I can't think of a way to keep the "seek" button functionality after taking apart the switch, due to the way it's constructed.
Here's a video I made on the matter. It's a terrible video, but it's just something I made on the fly while messing with the stereo: