View Full Version : Kaypro II always spinning both disk

Junior Ramos
May 10th, 2010, 05:18 PM
I have two kaypro II with the same problem, when power on both drive always is spinning. If removed the flat ribbon cable then do not spin. So I think the floppy controller in the main board are defective.
But I would like to know when the computer power on what suppose happen with the drive?
Any help will be appreciate.

May 10th, 2010, 09:09 PM
It's normal for a Kaypro II to spin the A drive up (top drive, usually) even without a disk as it searches for a bootable floppy. The drive's status light will be on, as well. IIRC, my Kaypro II only activates the A drive though, not both. Are both drives' in use lights illuminated?

May 10th, 2010, 09:41 PM
Individual control for 5.25" diskette drives didn't really come along until the PC. In the standard SA450-type interface, there are 4 drive selects, but only 1 motor control line. The usual way to do things was to chain drives on a single flat cable, changing the drive select for each drive on the cable. You could put 4 drives on a single cable, but the motors all went on or off at the same time.

When the PC came along, IBM figured that they could drop 2 drive selects and use one of them for a second motor control signal by using a twisted drive cable. The tradeoff is that you get only 2 drives per cable, but get individual motor control--and you can set the drive select on every drive to DS1 and let the cable do the signal-swapping.

There are a couple of older PC controllers (Ultrastor, DTC) that used otherwise unused pin 4 on the idrive interface to supply a third drive select (some fancy twising). And there was at least one DTC controller that allowed for 4 drives on a flat cable as an option.

Junior Ramos
May 11th, 2010, 04:26 AM
Thanks to Glitch and Chuck for response.
Both Kaypro II are 190k floppy. (81-149 and 81-146c eproms) When power on, both motor running always, only drive A illuminate.
and the screen appear place a disk in drive A. I place a disk but i don't see the head move for searching a boot sector.
When a computer power on should be spin and the stop?

May 11th, 2010, 06:13 AM
No, it will keep spinning until it either finds a boot disk or encounters an error. It sounds like your Kaypro is working fine, probably more a question of if the disk drives are operating at this point. Do you have the proper boot disk for the machine? A double-sided Kaypro disk won't boot it.

Junior Ramos
May 11th, 2010, 06:49 AM
The both disk are spinning, are this ok?
I have an original boot disk 2.2, But I make one with the Dave image. I use the 22disk to format disk, then write disk with image disk from Dave.
Then read the disk on 22disk and read with no problem. But the original disk don,t read in 22disk, maybe the original disk is damage.

If the computer is ok, when place a disk should be an error on the display is the disk is damage? due nothing happen when place a disk.
Thanks again

Junior Ramos
May 12th, 2010, 06:12 AM
Here my findings:
First thanks to Glitch,
I check again the other motherboard and found that the FD1793 floppy controller is damage, replace and right now boot perfect.
So I have 2 motherboard working, just need to found a floppy controller chip.

But has 2 floppy drive that no read nothing and one power supply damage.
The power supply should be around 225V in a Q2 but just have 120V. I check the Q2 and all component around, but all are ok.
I resolder all component and then clean the power supply.
I think this power supply was damage due all connector pin in the output DC volts was loose (cold or crack solder).
Any help please.
Also with the floppy drive.
Thanks again.