If the IBM is un bootable you are not going to be able to connect to it in this fashion.
You can remove the IBM hard drive and either fit it in an external drive case that accepts a laptop hard drive or get an adapter in order to slave the drive internally on a desktop computer.
With either of these methods you will be able to access the data assuming that the hard drive itself is not mechanically damaged.
You could also try troubleshooting the IBM itself from their web site:
http://www.ibm.com/support/us/