Bob I’m not sure but this is my guess?Does the 890 have a sound card built into it?Not same caliber but 590sg doesn’t and I have to use a winkeyer. The 7610 has its own sound card built in ? But with that said if ur getting intermittent cw that might not be the cause. Maybe someone with 890 will chime in 73 Dave N4cwz Sent from my iPhone