Yeah we had a customer that had one evap fan motor out for over a year, didn't get changed until we replaced the whole evaporator ass'y, because that fan was against a wall. Sometimes though, you can just unmount the evap ass'y and there is enough play to bend it sideways enough to access the other side without cutting the refrigeration lines. I actually like those Delfield evaporator assemblies, really easy to swap out once they start leaking, which is usually 5 to 7 years in my experience.
Seen this has happened multiple times: First tech goes out, replace t-stat. A month later, next tech goes out replace powerhead. A month later, next tech goes out, its out of refrigerant and replace the entire assembly (we rarely rebuild them, usually replace the whole assembly).
But dang, those Delfield mullion evaporator units just work great. Great airflow, they always pull down to low 30's, and really never freeze up (assuming all fans, refrigeration, tstat etc, working properly.) They pull the box down FAST. That's what I love about them. The wrapped cold rails also work great in my experience.
On the other hand, the 4400 series evaporator / cap tube, those style Delfields are very light duty and I am not a fan, especially on the open top design, they pretty much never hold temp properly especially in the pans; with only a single evaporator fan they just frost up continuously throughout the day and food gets warm, until it finally goes through a defrost, then it works until the first time they open a door or something, then its warm again the rest of the day. SLOOOOW to pull down, can't keep up with heavy usage or ambient > 78*f on the open top design.