I don't have a 62T baler, but I do have an Oliver 520 and a NH68. Same basic design.

Do you have a manual? You mentioned you've already tried timing, although you will probably need to do so again. 

I would check the knotter brake. Is it holding the needles in the &quot;home&quot; (most rear position in the needle frame) position? They should not creep down. 

I would check needle penetration. This will position the needles in the correct location in relationship to the bale chamber. 

I would check that the plunger safety stop is adjusted correctly. You don't want it in to soon or to far ahead of the needles. On my 520 baler the stop enters at the same time.

If you make any adjustments to the above you'll need to retime the needles. 

Two things come to mind about needle timing.

Are you measuring from the flat outside bottom of the bale chamber?

Did you have the needle drive clutch fully engaged before reinstalling the chain and did you have all the slack removed from the drive or top side of the chain?

I hope this helps.