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

["IceMan" <toomuch@spam.here>]

    Success!

    To make a long story short, one of the motherboard dram chips was bad:
after rechecking earlier this evening with the self diagnostic, and noticing
that it failed (stuck on RAM:) I then unsoldered all the 8 chips, soldered
sockets on and used my 64K expansion card's chips which were on sockets to
test it first. It immediately passed the test (KERNEL OK) so I tested the
ones I removed, one by one and found the faulty chip.

   So now, I have a working Apple IIe without the expansion and 80 column
board, but at least it's working! I need to find another 64k chip to replace
mine and get my expansion board up and running again.

   My disks all load like a charm, and now I can recalibrate my drives with
my copy program which has a drive speed test.
I played Norad and Transylvania, but that damn werewolf keeps eating me.
What memories and flash backs!

    Luke

"josephoswaldgg@hotmail.com" <josephoswald@gmail.com> wrote in message
1133314833.369654.112140@o13g2000cwo.googlegroups.com">news:1133314833.369654.112140@o13g2000cwo.googlegroups.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.
>