What could I be doing wrong? (My other POS-900W's do the same).
Incidenatlly, I have a screenshot (23Kb) of the display which I can
e-mail.

Well, you don't specify the frequency coverage of your other VCO's, MCL's
have a very high MHz/volt tuning rate and unless the tuning voltage is
absolutely quiet, they'll look pretty bad. (BOTH the positive AND the
negative leads shielded to ground?)

W4ZCB