Hello! I've recently acquired a pair of Panasonic D-3 decks (AJ-D350/AJ-D351) that I'm working to bring back into reliable operating condition. I've spent the last several weeks going through service documentation, performing board swaps, taking measurements, comparing behavior between machines, and generally getting far deeper into these decks than I ever expected.

At this point I'm less interested in basic troubleshooting suggestions and more interested in hearing from anyone with real-world experience calibrating and aligning D-3 machines. In particular, I'd love to connect with technicians who have experience with RF/envelope evaluation, servo adjustments, tape path alignment, error-rate interpretation, and the factory calibration procedures used on these decks.

I have one machine that will intermittently play and another that exhibits a different set of transport and playback-related issues. I've gathered a considerable amount of diagnostic information already, but I'd prefer not to flood this initial post with pages of measurements and scope readings unless someone has experience in these machines and is willing to dig into the details.

D-3 expertise seems increasingly difficult to find, so if you've worked on these decks in broadcast environments, Panasonic service centers, or engineering departments, I'd greatly appreciate any guidance, calibration notes, or lessons learned.

Thanks in advance. I'm eager to learn and document the process as these machines are brought back to life!