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

["IceMan" <iceman@nospam.net>]

  Joseph,

  replies underneath:

"josephoswaldgg@hotmail.com" <josephoswald@gmail.com> ha scritto nel 
messaggio 1133314833.369654.112140@o13g2000cwo.googlegroups.com">news:1133314833.369654.112140@o13g2000cwo.googlegroups.com...
> I assume you actually mean an Apple IIe, if the 80 column & 64k are the
> same card.

   Yes - sorry, I have a IIe - I keep referring to it as an Apple II...

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

  Well I tried this and it doesn't give any apparent error, just a prompt if 
I remember correctly (I did this last week) and to resume I need to reset 
again.

> 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?

  Yes, these are the first things I did: I ran all the tests with just disk 
controller (no 80 coloumn or centronics Graphicard).

> 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.

   Yep, I did this too: I reseated all the ICs I could plus I resoldered 
some of the ones directly soldered to the board.

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

   Yes, I meant just that - how else would one call it? I took the card out 
and reheated the pins to see if something changed, but it didn't.

> 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.

   Interesting, I will check this (I am in Europe, 50Hz AC).

> 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.

   There are only 2 pots on the DuoDrive logic board: one for one drive 
section and one for the other. I always mark the original position to which 
they are set to again now - there are no other pots on the duodrive board.

   I am going to buy another floppy controller card (and a superserial 
card!) in the mean time just in case. It is strange though, that when I cold 
boot the Apple with one of my copyprogram diskettes, I get a raster image 
which is garbled. Then if I warm boot the Apple, I get another raster image 
which is less garbled than before. If I cold boot it again, I get the same 
"more garbled" image I got the first time. So maybe it's a memory problem or 
maybe it is simply because the video buffer is "wiped" with a warm boot and 
not with a cold one? I don't know here what the procedure is, but it's 
either that, or some memory banks are defective - but wouldn't the self 
diagnostic give an error?

  Thanks for the tips. I will fight to the last.

          Luke