Re: Hints/feedback on disk reading failure on Apple IIe

["josephoswaldgg@hotmail.com" <josephoswald@gmail.com>]

IceCool@Digidude wrote:
> Ave Apple II enthusiasts!
>
> The other day I decided to break out my good ol' Apple II with DUODRIVE and
> monitor and give it a go after some 15 years of inactivity. My Apple has an
> 80column + 64K explansion card, a Practical Peripherals Graphicard and the

I assume you actually mean an Apple IIe, if the 80 column & 64k are the
same card.

In which case, does it pass the self-test (control-closed apple-reset)?

Have you tried removing and re-inserting the disk controller, removing
the graphicard, even removing the 80column & expansion, and running
just with 64k built-in and the disk drive only?

With the minimal system, you can then "scootch" any socketed chips
(push down on the chip, possibly having *slightly* lifted it, to scrape
off any corrosion in the chip-socket contact. Likewise with the
controller card.

There isn't any conventional A/D converter; just an analog read
amplifier that gets clipped to logic levels by the controller card.

Unfortunately, the speed pots and heads were probably the least likely
to age in storage. You should be able to find the right speed back with
a (fluorescent?) lamp acting as a 120 Hz (or is it 60?) strobe light,
illuminating a marked ring on the drive motor, which should appear
stationary when properly set to 300 rpm. I think there might be two
rings: one for 50 Hz countries, one for 60 Hz countries.  If you
tweaked some other pot (like one affecting read/write amplifier
settings) you might be SOL without a calibrated test diskette that
presents a known field pattern to the read coil.