Hi
Did anyone here had problems with a play in the headset?
1) Check your steerer tube length. You may not have left enough space to compress the headset.
2) Check your compression ring to make sure it's seated properly.
3) Check your compression plug to see if it's slipping.
4) If you're locking up your steering but still getting play in your headset, check to see if you have too much space between your top cover and compression ring.
For 1, I just used a spacer above the stem. For 2, the compression ring was seating fine most of the time, but it was frustrating enough that I got a new headset with a different compression ring. For 3, I had to use a different compression plug.
When all those were taken care of, I started locking up the steering trying to tighten the headset, so it was progress at least. My LBS sold me some spacers that sit above the compression ring. That finally did the trick.