Re: Looking for technical information online

["Bryan Parkoff" <BParkoff@satx.rr.com>]

    I suggest that you can obtain "Repair Apple II+ & //e book.  It does
have troubleshooting procedure that will provide you more information.  It
gives you all the list of 74xx chips and type of other chips that you need
to replace in order to restore Apple II+ & //e back to normal.
    I plan to post on the web, but I must get a permission from the author
because of copyright.

--
Yours Truly,

Bryan Parkoff
BParkoff@satx.rr.com
"Michael J. Mahon" <mjmahon@aol.com> wrote in message
20030311210825.19751.00003448@mb-cu.aol.com">news:20030311210825.19751.00003448@mb-cu.aol.com...
> In article <MPG.18d8abc67cda5f91989937@news.t-online.de>, Michael J.
Sch�lke
> <mjschuelke@hotmail.com> writes:
>
> >Where can I find hardware information on the Apple II (in its various
> >incarnations -- II+ and IIe would be especially interesting ATM) online?
> >The more technical and the more exhaustive, the better.
>
> Unfortunately, the really great stuff doesn't appear to be on the web.
>
> Sather's "Understanding the Apple ][" and "Understanding the Apple
> //e" are, in my opinion, the definitive works.  One or the other comes
> up on eBay every once in a while, and various used booksellers get
> copies from time to time.
>
> >Currently, I'm looking mostly for repair related information, as there
> >is a dead II+ sitting on my desk. I've already found the Red Book, and
> >while it contains all the schematics, it doesn't have the circuit theory
> >backing them -- descriptions of how the circuits work, which signals are
> >to be expected at which points, etc. Of course, I could work all of
> >these out on my own, but that takes time -- a lot of time.
>
> The good news is that you can almost certainly fix it without getting
> a deep understanding of its innards.
>
> First, remove any peripheral cards that may be in the slots, except a
> memory card in slot 0--no need to make the problem more complicated
> than necessary.  Then try it out.
>
> If it doesn't "beep" when you turn it on, then the CPU is not running
> far enough in the reset code to do that--it's a good quick test of whether
> the II is alive.  If no beep, turn off the power and loosen and re-seat
each
> of the socketed ICs.  This will correct most problems with oxidized IC
> leads & sockets.
>
> Check that memory chips are present in all sockets across the three
> rows of memory sockets.  (Actually you can get it to work with just one
> or two rows full, starting at the back row, but three is most common.)
> It is very common for the memory chip in the back row nearest the
> power supply to be missing, because a 16KB card was pulled, and the
> chip that belong in that socket was relocated to the card.  If the 16KB
> card is present, then there is a 16-pin DIP jumper that goes between
> a socket on the card and that socket on the main board.
>
> Then try the power again.  If it's still no-go, get out your multitester
> (you need one!)  and measure the voltages at the power supply
> connector.  They should all be within +/- 10% of spec (hopefuly
> better than that).  Obviously, +5v is critical--if it isn't there, then
> nothing can work, and you have a power supply problem.
>
> If the voltages are present, and the chips have been re-seated, then
> you have a more "interesting" problem.  ;-)
>
> Why not give this a try (unless you already have) and get back to
> us about what happened.
>
> >So, can you help me? The web searches I tried before always drowned me
> >in superficial results.
>
> Of course, even after you get it working, it's still a great idea to learn
> more about the design.  Although there are many helpful documents
> on the Net, you will probably still want to get the "real stuff".
>
> When perusing the Web, it's helpful to have some good starting
> points.  Rubywand's excellent A2 FAQ is a fine place to start, and
> it has lots of useful links to other sites:
>
> http://home.swbell.net/rubywand/A2FAQs1START.html
>
> Enjoy!
>
> -michael
>
> Check out amazing quality 8-bit Apple sound on my
> Home page:  http://members.aol.com/MJMahon/