Re: Getting ap2222pc on the Apple II

["MechCD" <mechcd@bluebottle.com>]

Today I found out it was the power supply. I swapped in a 1984 one and it
works great now. I haven't tried the link yet, but the joystick works. I'll
keep the ceramic caps in mind if something goes wrong again. It's a regular
//e, but might have the Enhancement Kit. I don't really know yet.

Thanks for the info!

"Michael J. Mahon" <mjmahon@aol.com> wrote in message
20040301234852.18203.00000599@mb-m06.aol.com">news:20040301234852.18203.00000599@mb-m06.aol.com...

>
> The buttons on a joystick are switches that connect the pulled-down
> PBn input to +5v when they are pressed.
>
> The fact that pressing one of your buttons causes a short of +5v to
> ground (which explains the symptoms you describe) indicates that
> the corresponding PB input is grounded.  This would, of course,
> also explain why the PC cannot talk to the Apple II.
>
> If you have a Platinum //e, this could be explained by a shorted
> 0.1uf bypass capacitor (near the external joystick port).  On any
> //e it could be a short in the joystick connector or in the joystick
> cable.
>
> Or, worst case, ESD or severe overvoltage could have caused the
> PB logic input itself to be shorted to ground.  This is an unusual
> failure mode, but you have been connecting cables to the input...  ;-(
>
> (It is interesting that this kind of short of +5v to ground can occur
> on PB2 for any machine that has the shift key mod installed (as
> the platinum //e's do by default), if the shift key and the button
> corresponding to PB2 are both pressed at the same time.)
>
> -michael
>
> Check out amazing quality sound for 8-bit Apples on my
> Home page:  http://members.aol.com/MJMahon/