How to use Accubias feature on Onkyo tape deck?

I own the TA-2090 which has this feature. From memory, just insert a tape and push the accubias button. The machine does the rest! I believe you'll want to set the recording level to an appropriate level and also turn down the volume on your preamp. The machine lays a tone on the tape, rewinds to the start of the tone, then uses it to set an optimal bias level for the particular tape-type you're using. My TA-2090 needs some work if you know a good technician.
Thanks, Ken

Oops! It just dawned on me (remember, this is from memory)... I think you've got to set-up your deck like you're ready to record... i.e. 1. press pause 2. press play-and-record at the same time 3. press the accubias button. You're welcome...

If you haven't figured it out by now, all you have to do since you have a three head deck is start your recording and while you monitor the recording, adjust the accubias until you like how it sounds and then restart your recording. If you have a two head deck it's more or less by recording on one setting and going back to see how it sounds and repeating the process until it sounds good to you. If your recording on normal bias cassettes your gonna use less bias, if your recording on high bias cassettes your gonna use more bias.