Jumpering for NEC FD-1165H 8-inch floppy drive

From: Tony Duell <ard_at_p850ug1.demon.co.uk>
Date: Sat Jan 3 12:39:46 2004

>
> On Fri, 2 Jan 2004, Nico de Jong wrote:
>
> > From: "Steven N. Hirsch" <shirsch_at_adelphia.net>
> > > Title says it. Can anyone point me to online data for this elderly
> > > device?
> >
> > No, but I have the straps for teh FD1165-FQ, as used in my media conversion
> > systems.
> > I am looking at a "naked" drive right now, with the front towards the
> > right. I can see a number of straps, e.g. the one called US. This one has a
> > jumper on the righthand part, and is therefore designated below as US 1
> > Are you sure the voltages are on the correct pins ?
>
> The "H" model is older and uses a square 6-pin Molex connector (same as
> all my other 8-inch drives), so I'm sure the voltages are correct.

Has this drive ever worked in this system? If not, you might be missing
some voltage (like -5V) that's not needed by some drives. Have you
actually checked the PSU voltages at the drive with a voltmeter?

>
> There are some notable differences between the FD1165H and "-FQ" models.
> After reading the service manual on Al Kossow's site (thanks to all who
> pointed me there), it seems that the motor is supposed to turn on disk
> insertion and is not gated by select or head-load signals - at least on
> the FQ variant.

That is quite normal on 8" drives. The mains-powered models keep the
motor running all the time.

>
> So, why on earth would (2) functional drives just decide not to spin? In
> the interim, I installed a (mis-matched) pair of one-each Qume and Tandon
> 1/2-ht. drives in the same box. These work fine, indicating that I'm not
> dealing with a power-supply or data cabling problem.
>
> A little poking with a voltmeter shows that the motors in the NEC units
> are not receiving power. Once again, the head stepper and head-load are
> working properly on these units. Another symptom: The NEC units have (2)
> status LEDs on the front bezel; ready and active. The ready LED is
> supposed to illuminate when power is applied and a diskette is present.

That's often turned on (as is the READY signal on the interface) by
detecting valid index pulses. So if the disk is not turning, the drive
will not become ready

> It does not.
>
> Anyone have a suggestion for troubleshooting?

Yes. Trace back from the motor to find how it's controlled (or if you
have a schematic, look there). Find out what signals are needed to turn
the motor on (e.g. a disk-inserted sensor) and find out which are
missing. Find out where the motor switching circuit gets its power from,
and make sure that's present and correct.

-tony
Received on Sat Jan 03 2004 - 12:39:46 GMT