famicomaster2
Experienced Member
These drives do not have nearly as close tolerances as anything modern. I've had my KC-20B open several times and I still have no further bad blocks than the factory defect list of 2. Don't leave fingerprints or oil on anything, don't do it in a wood shop, and don't smoke while you're doing it and things will generally be fine.
Don't be blatantly stupid. These drives do not have a particulate filter. Do not operate the drive with the cover off, as the airflow is not sufficient towards the edges of the platters and the heads will "crash" so to speak.
If you go the glove route, get POWDER FREE gloves, non-latex preferably.
The KC-20B does not have a rubber bump stop, it is a metal peg affixed permanently to the lower half of the chassis and there is an adjustable set screw to limit outward motion. This screw should NEVER need adjustment during normal operation, if you do turn it DO NOT allow the heads to move further out, once they're off the surface of the disk it's over.
You should be able to rotate the stepper gently with the tip of your finger without even opening the drive, the other end of the shaft is visible from the bottom. You will feel it rotate in one direction and not in the other if it is against it's stop. One or two drops of machine oil down the shaft of the stepper is more than enough. These drives have an exercise mode, place a jumper on the block labelled "W1" (below drive select jumpers) and operate the drive for a few minutes. It should work the oil in on it's own. If the stepper doesn't move at all with this, you can manually rotate it a few times (do not do this too much as it can damage the heads or platters) to get it started.
The seek test for Kyocera KC-20B is to single step to the track 0 sensor, fast seek to cylinder 615, back to cylinder 10 and single step back to track 0. This tests the track 0 sensor and that the stepper does not miss any steps. If the drive reaches track 0 during the fast seek, the stepper is missing steps and is probably just stiff with low oil. If the drive never leaves track 0, the stepper is assumed to be damaged or failed. If the drive never reaches track 0 the sensor is assumed to be failed or out of adjustment.
There is a track 0 line on the "control" section of the ST412 interface (the larger, 34 pin edge connector). Attach a spare cable and jump the drive select that the disk is configured for. This should "always" select the drive and it's access lamp should stay illuminated when powered. With a scope attached to the track 0 line, you should see it strobe once or twice during seek test and then stay high at the end.
Hope this helps, sorry I didn't see this thread sooner. These are very reliable drives, despite being horribly slow (60ms+ access time!).
EDIT: The correct jumper is labelled "W1" for the butterfly seek self test, not TP1.
Don't be blatantly stupid. These drives do not have a particulate filter. Do not operate the drive with the cover off, as the airflow is not sufficient towards the edges of the platters and the heads will "crash" so to speak.
If you go the glove route, get POWDER FREE gloves, non-latex preferably.
The KC-20B does not have a rubber bump stop, it is a metal peg affixed permanently to the lower half of the chassis and there is an adjustable set screw to limit outward motion. This screw should NEVER need adjustment during normal operation, if you do turn it DO NOT allow the heads to move further out, once they're off the surface of the disk it's over.
You should be able to rotate the stepper gently with the tip of your finger without even opening the drive, the other end of the shaft is visible from the bottom. You will feel it rotate in one direction and not in the other if it is against it's stop. One or two drops of machine oil down the shaft of the stepper is more than enough. These drives have an exercise mode, place a jumper on the block labelled "W1" (below drive select jumpers) and operate the drive for a few minutes. It should work the oil in on it's own. If the stepper doesn't move at all with this, you can manually rotate it a few times (do not do this too much as it can damage the heads or platters) to get it started.
The seek test for Kyocera KC-20B is to single step to the track 0 sensor, fast seek to cylinder 615, back to cylinder 10 and single step back to track 0. This tests the track 0 sensor and that the stepper does not miss any steps. If the drive reaches track 0 during the fast seek, the stepper is missing steps and is probably just stiff with low oil. If the drive never leaves track 0, the stepper is assumed to be damaged or failed. If the drive never reaches track 0 the sensor is assumed to be failed or out of adjustment.
There is a track 0 line on the "control" section of the ST412 interface (the larger, 34 pin edge connector). Attach a spare cable and jump the drive select that the disk is configured for. This should "always" select the drive and it's access lamp should stay illuminated when powered. With a scope attached to the track 0 line, you should see it strobe once or twice during seek test and then stay high at the end.
Hope this helps, sorry I didn't see this thread sooner. These are very reliable drives, despite being horribly slow (60ms+ access time!).
EDIT: The correct jumper is labelled "W1" for the butterfly seek self test, not TP1.
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