Re: J23 on the GS motherboard.

["Roger Johnstone" <rojaws@es.co.nz>]

----------
In article <389A43AE.3FB73D9A@dcnet2000.com>, Phoenyx <quazar@dcnet2000.com>
wrote:


>Well, I decided to pull my GS apart and do some cleaning. On
>the front of the motherboard, there is a card edge style
>connector numbered J23 with 13 fingers on the top, I didn't
>check the bottom though. Does anyone know what the purpose
>of this connector is for? I know it's on the rom 1 and rom 3
>boards.
>
>Thanks,
>Phoenyx

According to my trusty Apple IIgs Hardware Reference, J23 is the burn-in
edge connector. It's a 26 way connector, so must be double-sided. Most of
the pins are power supply, presumably used for powering the board with no
supply plugged into the normal connector.

pin   use           pin    use
-----------------------------------
 1    +5V            14    AN0
 2    +5V            15    -5V
 3    +5V            16    -5V
 4    +5V            17    AN1
 5    SW0/OAPL       18    AN1
 6    SW0/OAPL       19    0V
 7    +12V           20    0V
 8    +12V           21    0V
 9    DIAGSW         22    0V
10    DIAGSW         23    U18TEST (not used on 1MB motherboard)
11    -12V           24    U18TEST (not used on 1MB motherboard)
12    -12V           25    0V
13    AN0            26    0V

SW0/OAPL is obviously the open Apple key. DIAGSW is presumably a diagnostic
mode switch. AN0 and AN1 will be the game port annunciator outputs, used for
receiving data from the diagnostic program running in the GS? U18TEST, I
don't know. It's only marked on the 256KB motherboard schematic.

Use this info at your own risk!


Roger Johnstone, Invercargill, New Zealand
http://homepages.ihug.co.nz/~rojaws
------------------------------------------
Programming today is a race between software engineers striving to build
bigger and better idiot-proof programs, and the Universe trying to produce
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