[Coco] Calibrating disk drives

[Spencer]

Greetings all.

I have a 26-3022 and 26-3029 drives;  both write to disks fine, but when I put one disk from one into the other I get the dreaded ?IO Error.  Someone told me one or both drives are out of calibration and will ultimately fail 100% at some point.

I've never calibrated drives myself.  Is this something that can be done at home or is there specialized equipment needed for this?   Or is there anyone out there that knows a place that can recalibrate them?

Thank you!