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Re: Technical question... continued !
As the "Apple disk drive guru of New Mexico," I have many dozens of the
74LS125 and ULN2003 chips.
HOW ABOUT THIS: Send me $1.00 and I will mail you BOTH CHIPS, including
postage. (Its almost pointless to drive around town looking for these
chips when I sell them, 2-for $1 !
Steve Buggie
200 College Rd.
Gallup NM 87301 buggie@unm.edu
Patrick Schaefer (pa.schaefer@fz-juelich.de) wrote:
: eib wrote:
: > 1) The Apple II does not boot. It makes a sort of "bi....bi....bi..."
: > noise, like a short boot beep that loops.
: > 2) The Apple boots, and the drives load nothing (the red light is lit,
: > but it does not read the disk).
: You plugged in the drive cable the wrong direction (180=B0 rotated). This=
: will kill the 74LS125 and the ULN2003/XR2003 on the Disk ][ Analog
: Board. Try booting for some time and you'll see some smoke coming
: outside the drive. This is the 2003 chip.
: Replacing the chips is easy. Get a new one from your local electronic
: shop, remove the old chip from its socket and insert the new one. With a
: working 2003 you should be able to move the RW head ('PR#6' -->
: 'grrrzzz'), the 'LS125 is required for read/write operations.
: Patrick