on-one track hub bearings

The back wheel on my pompino has gone wobbly. Are the black on-one branded track hubs adjustable to get rid of play? (I’m sure some sealed bearing hubs are adjustable) I tried tightening up the spacer-nuts and lock nuts as per cup and cone hubs but it’s still wobbly. Failing that what bearings do I need to replace them and how difficult is it?

I’ve looked on the o-o website and cant find owt.