[Tfug] Any tips for diagnosing possible hardware problems?

[Bexley Hall]

--- Richie Smit <rfs_lists at mac.com> wrote:

> Bexley Hall wrote:
> > Very *loose* rule-of-thumb:
> ...which unfortunately doesn't hold true for
> floppies! Drat!

The operative word (above) is "loose"  :>
(i.e. if you have to *guess*, use that to bias
your first guess!)

Having said that, I took out my box of spare
floppies and checked each of them:

Mitsubishi MF355C  3.5"       Agrees
Teac FD-505 3.5/5.25 combo    Agrees
Mitsumi D359T[56]  3.5"       Agrees
EPSON SMD-1300  3.5"          Agrees
Teac FD-235HF   3.5"          Agrees

I didn't open any of my existing machines to
verify this on the other drives present, here.

The only (floppy) drive that did NOT agree with
this "1 near power" convention was an NEC FD1165
(but I seriously doubt you'll have one of those
in a PC!  :> )

I didn't bother checking Sun/SGI/etc. floppies
as I suspect there is little interest in that, here.

I recall that there are also some deviations from
this wrt SCSI peripherals but I'm not excited about
dragging out more boxes of parts just to prove
that to myself  :>

[Note that in addition to the key in the connector
shell, some floppies have pin 3 (4?) used as a key.]

> I just so happen to have a working box here to look
> inside. The floppy 
> connector's pin 1 (red on the cable) is on the left
> as you look into the 
> rear of the drive. Opposite way round to the IDE
> devices, which do 
> indeed have red/p1 next to the power connector.

Note the position of the power connector on the
floppy drive, itself!  It is usually on the opposite
side when compared to IDE drives (hence the reason
that I phrased my mnemonic wrt the power connector
and not "left" or "right")

> If it works, I wouldn't let it worry you. There were
> a bunch of 
> otherwise identical machines at my last place of
> work, and about 5% had the floppy light always on.

If the LED is lit, something is probably wrong as
it indicates that the drive is actively selected
all of the time.  Some machines *can* be using this
to automatically detect the insertion of a floppy.
But, it could just as well be "something wrong".

I don't like blindly accepting things as The Way
They Are without understanding WHY they are that way.
YMMV, of course...  :>

--don

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