IBM 5162 - Known Problems/Issues
Some early 16-bit cards are too tall for the 5162's case.
Floppy disk drive - Pin 34
In the earlier IBM 5150, 5155 and 5160, the supplied IBM floppy controller (photo) does not 'care' about pin 34 - because the controller does not monitor pin 34 of the cable connector.
However, in the IBM 5162, the pin 34 situation is much different. The controller supplied in the IBM 5162 monitors pin 34. This is the same as what occurs in the IBM 5170.
1.2M floppy drives in an IBM 5162 are required to generate a DISK CHANGED signal on pin 34, a requirement of the IBM 5162's BIOS. Failure to observe the requirement can result in corrupted floppy disks.
360K floppy drives in an IBM 5162 are not required to generate a DISK CHANGED signal on pin 34, possibly because the BIOS authors knew that most 360K drives cannot generate such a signal. However, some 360K drives generate a READY signal on pin 34. A READY signal is a problem for the 5162. If you intend to connect a 360K drive, the simple rule is, disconnect pin 34. Some 360K drives have a jumper that can be removed to achieve that (e.g. the JU-455-7 has an 'RY' jumper).
More information about this subject is in the 'Diskette Changeline' section on pages 781 and 782 (PDF pages 814 and 815) of the document here. In the first sentence of that section, 'standard PC floppy controller' should have instead been 'standard AT floppy controller' to avoid confusion.
Deteriorated lubrication in floppy disk drive
It is often found that in 5.25" floppy drives that have not been used in many many years, that the lubrication in the drive has deteriorated to the point where it 'gums up' and stops the drive from functioning properly.
This is commonly seen on the rails that the head carriage slides up and down on. Deteriorated lubrication there results in the inability of the head carriage to move properly, or in extreme cases, not move at all. By hand (and with power off), you should be able to freely move the head carriage along its rails. You will experience some slight resistance presented by the stepper motor.
What is required is to clean the rails of the old lubricant, then followed by application of new lubricant. Myself and others have found a silicone based lubricant to be satisfactory. I sometimes use silicone spray, but there is a tendency for the spray to get to areas where it should not go. Otherwise, I use 'silicone dielectric compound', a particular type of silicone grease that I also use to get rid of any squeak sound from the drive's front panel latch.
If in any doubt, clean/relubricate the rails. The clean/relube is a worthwhile maintenance activity even if it doesn't fix a faulty drive.
Floppy formatting problem
"IBM ships patch disk for XT 286 to fix DOS 3.2 formatting errors."
Note: Do not format (or write to) a 360K floppy in a 1.2M drive, unless you are aware of the ramifications.