Re: digital input at cassette port

["mspangler" <mspangler@gemsi.com>]

Michael J. Mahon wrote:
> bieling@terra.es wrote:
> > Looking at the Apple II Red Book schematic, I would do the following:
> >
> > 1.- Remove the 741 OpAmp.
> > 2.- Substitute R41 for a 330 ohm resistor.
> > 3.- Connect the cassette input to pin 6 of the now empty 741 OpAmp IC
> > socket.
> > 4.- Clamp H14-4 to GND and to +5v with a pair of diodes.
>
> That will certainly do it--but the clamping diodes protect the new
> input better than any of the original ones!  ;-)
>

thanks to  www.turbo-2.com/apple/pdf/a2rb.pdf, I was able to find out
that R-41 on the II is the same as R-20 on the IIe. And that there is
no 12k resistor on the input of pin 2 of the op-amp on the II.

That should let me fix it. 

Thanks;