Re: Help! with Apple ][ plus

[Rubywand <rubywand@swbell.net>]

Jim Frankel writes ...
> 
> Hello all,
>     I'm trying to get a 'plus' working, and I've run into a wall.  I was
> wondering if anyone had any advice to offer.
> 
>     The problem is that when I try to book from a disk, the computer
> crashes and throws something that resembles this on the screen (it's not
> always the same, but it seems to like EC62 and some random hex
> values.....).
> 
> EC62-    A=05  X=E7  Y=00  P=3D  S=E3
> *
>     Every once in a while "Apple II" will appear at the top of the
> screen before it dies.
>     So yeah... and if I press reset after this, CATALOG works, but not
> much else.  I certainly can't run anything, but the LOAD command at
> least acts like it's working.  I can type in programs by hand, and that
> seems to work.
> 
>     I got a new disk drive and controller card, but the exact same thing
> happens, so I'm assuming it's a problem with the motherboard.  I have
> the controller card in slot 6, and beyond that there doesn't seem like
> anything else I could be doing wrong.  Does anyone have any suggestions?
>

 ....

     The output you are getting when there is a crash (the address and
register displays) is typical of what happens when a Break ($00)
instruction is encountered. Address $EC62 would normally put you in one
of the Applesoft BASIC ROM's.

     If, say, due to bad memory or corrupted code on-disk, you were
getting sent to a $00 in ROM, a Break would occur. However, there seems
to be no code in this ROM area ($ECxx) which would produce a Break
output display showing "EC62".

     You do not say whether or not your II+ has a Language Card (16k
card) installed. Probably, it does since this is a standard addition
needed to bring the II+ up to "64k" needed to run a number of programs.

     First, try booting several different diskettes. If most of these
work okay, your problem may be with the particular diskette and/or a
dirty disk drive R/W head. If booting other diskettes does not help,
continue on ...


     Here are three guesses about the source of your problems:

1. One or more of your ROM IC's is making poor contact in its socket.
The ROM's are the six big IC's in a row below the 6502 on the
motherboard. Scootch up and resocket each ROM IC.

2. Your Language Card is making poor contact in its Slot. Remove it,
unplug the cable from the motherboard, and clean the card contacts with
alcohol. Re-plug the cable and reinstall the card in its Slot making
sure to line up card contacts with Slot contacts.

3. One or more RAM memory IC's is making poor contact and the resulting
bad code is switching in the Language Card when it should not be
switched in. Try scootching up and resocketing each RAM chip.


     Good luck; let us know what happens.



Rubywand