My 990 has started to drift (more loke a wobble) a few Hz, most noticeable on 24 and 18, but then, that's where I spend most of my time. It seems to occur after switching bands, changes a little on both Tx and Rx, and then stabilizes. The readout does NOT change. It also seems to be intermittent, just to make it more impossible to pinpoint. Comments?? Harry N2ERN