We have the ST8001+ display and last season it began developing a "jump" when I rotated the course selector... so one click, meant to be a one degree modification, might have actually changed 3-4 degrees.
I talked to
Raymarine, and they suggested NOT replacing with their
current control
head... because the new unit doesn't have some of the same commissioning functions the 8001 has... so in case we ever needed to recommission the AP, that might be problematic. (Although it does appear we could use the new unit for most things, save the old in case we need to temporarily reconnect to do a recommissioning, etc.).
Instead, they suggested I send the unit to Seawire
Marine in
Miami. Did that, they repaired, all good. I suspect they can deal with display issues too... or you may be able to buy "tested/certified" (?) display
parts from them... or maybe they're even the vendor you're seeing on eBay.
-Chris