[TenTec] Orion 1 slow to reach full output/muffled CW

[Jon Zaimes AA1K]

When I key my Orion 1 (v. 1.373b5) the red LED at first lights but then 
goes out as I key, and the signal sounds muffled on another RX.

When I hold the key down and watch an output meter, the output starts 
out low and then slowly rises to full output (and the LED comes on).

Any ideas what's happening? Adjusting the keying rise/fall has no effect 
on this problem.

73/Jon AA1K