Re: I'm a newbie all over again..!

[John Le Febvre <John@klatch.demon.co.uk>]

In article: <12DEC199504534541@vax2.concordia.ca>  spector@vax2.concordia.ca (Mitchell Spector) writes:
> 
> In article dempson@atlantis.actrix.gen.nz (David Empson) writes...
> >
> >In article <4a86la$hpf@acme.freenet.columbus.oh.us>,
> >Dave Althoff <dalloff@freenet.columbus.oh.us> wrote:
> >> John Le Febvre (John@klatch.demon.co.uk) wrote:
> >> : There is a very small 'patch board' on the lower right of the m/b
> >> : (towards the front).  Anyone know what it's for?  Just curious...
> >> 
> >> A little circuit board attached to the motherboard somewhere near the
> >> Sound RAM?  I believe that means that your motherboard is, like mine,
> >> actually an original ROM OO upgraded to a ROM 01.  Dunno what it does,
> >> just that it's part of the upgrade.
> > 
> >I don't think I've ever seen one of these.  My ROM 01 (originally 00)
> >doesn't have this.
> 
> 	Yes it does, he just didn't describe it very well.:) I believe 
> they're talking about the set of silver fingers (simular to that of
> a slot card) located on the far left corner of the motherboard. It is
> not normally visable, being covered by the plastic extension tab where
> the power-light is. The connector is used only for factory testing.

Nope.  It's definately a patch board, on the RIGHT side of the motherboard.
Look at the asterisks on your diagram below.  The board is about 0.25" by
about 0.5" and has two transistors and a couple of resisitors on it.  
Somebody else pointed out that it was probably a patch to improve the
sound output of the board and reduce noise.
I will get more info tonight and post for future reference.

> Here's a quick cut-out diagram drawing I did that shows it:
> 
> :
> : 
> |L                    Sound RAM   _________
> |     Standard RAM     _______   |         |
> |    _______________  | _   _ |  |         |   ****
> |   | _   _   _   _ |  |X| |X|   |         |   **** 
> |    |X| |X| |X| |X|   |X| |X|   |_________|    PATCH BOARD
> |    |X| |X| |X| |X|   |X| |X|    Sound GLU
> |M   |X| |X| |X| |X|    ~   ~
> |___  ~   ~   ~   ~                   - - - - - - - - - - - - - - -            
>  ___| 1   2   3   4  5  6   7  8     9    
> |.........       _                          <- (Tab extension) ->
> ||||||||||      | |____________________________ _ _ _ _ _ _ _ _ _ _
> ~~~~~~~~~~~~~~~~~
>    		
>            Overhead view of ROM 00/01 Apple IIgs motherboard
> 
> 
> (Note dotted line which shows what area is covered by tab)
> 
> >David Empson
> 
> Mitchell Spector

-- 
John.
john@klatch.demon.co.uk