When we look over the front of the screen it is not uniform ?

When installing display you should stop and evaluate after each row to ensure alignment, there is lots of adjustment to be made by adjusting the 4 affixing bolts to each cabinet AND checking the interconnecting locks between cabinets have in fact been locked properly.

Also there can be occasions where the plastic mask unseats which will cause this affect but can be remedied by carefully re inserting into position.

Whilst some adjustment can be made post install, it is much easier to assess and align at the end of each row / column.