I'm v. rusty on ADATS, but I'll take a stab. Working from leaky memory and not tons of experience with ADATS, so take everything I say with a grain of salt.
Error messages can prevent the deck from proceeding. The transport mechanism is the weak link in an ADAT; it will set error messages very often. IF you can find a tech that worked on VHS machines, he should be able to fix the problem, but he/she'll be hard to find- it's been decades since VHS machines cost enough to fix instead of just trashing 'em and buying another one.
Good to be back, BTW.
Yeah, I'm a mod. But I'd rather be a rocker.