REPOST - DUE TO NET PROBLEMS

Hi,
   I have problems with the FDHD on a IICX that EKG reports is ROM
revision 376. I had reports that this Mac was having trouble 
formatting disks and by the time I got to it, the FDHD just would
not respond although all other functions were fine.

I checked the voltages on the DB19 external drive connector and pin
6 showed no volts with 7 and 8 giving 25volts unloaded. The power 
supply is an Astec and I sent it away for repair.

With the power supply reinstalled, I now get the following error:

With the internal FDHD connected, the Mac boots fine but on completion
of boot cycle an alert displays "The disk is unreadable - do you
want to eject it?". For every combination of response, the alert 
reappears within approx 2 seconds and this error is continuous. The
FDHD does spin but there is no head seeking and the FDHD is incapable
of ejecting the disk. This error sequence occurs regardless of whether
there is a floppy in the drive or not. Pin 6 on the DB19 external 
connector shows 1.2V, pins 7 and 8 show 10.75V.

With the internal FDHD disconnected, the Mac boots fine and works great 
(MacEKG reports no errors). The DB19 external connector now shows
no voltage on pin 6 but pins 7 and 8 show 10.75V.

Now, the internal FDHD may be fubar, but I have an apple 800K external
drive that gives exactly the same symptoms as the internal drive when
connected to either the external DB19 or the internal connector at J16
(after suitable surgery to the external drive). The voltages at J16 
(with the internal FDHD disconnected) are as follows:

	PIN	Volts	PIN	Volts
	1	-	2	5
	3	-	4	5
	5	-	6	5
	7	-	8	-
	9	-	10	5
	11	-	12	-
	13	10.75	14	5
	15	10.75	16	5
	17	10.75	18	-
	19	10.75	20	5

This machine has a SWIM which I don't think EKG tests. I have tested all
diodes and pica fuses and can find no problems. Does anybody have any
ideas ?

                        Best wishes,
                          Woody.

                               Paul Woodman  