Went out to a 25 other day, customer reporting it keeps blocking up.
revealed to be main ball motor failed, head was fine.
Had been on an aerial wiring / house job for previous 3 hours so was short of time and thought just swap out spine assy with good motor as it's cheaper and much faster for me to do in the field.
I tried to fit customers head to my swap out spine and the bugger wont clip on as it's offered up.
Noticed this difference on yoke face...
Never seen that in last 8 years.
Please don't beat me up - i bet it's a common occurrance ?