Apple II+ keyboard weirdness (help with repair)

["Rob Diehl" <rkcdiehl1@bellsouth.net>]

I got out our family's old Apple II+ computer after 10 or so years of
sitting in the closet. My dad loaned it out to a family with some kids and
ever since then the keyboard stopped working. Well, that was a long time ago
and I am on a mission to repair it. Everything in the computer works great
except for the keyboard which gives absolutely no input to the computer
under any circumstances except for the reset button (which doesn't really
count I don't think, since it is somewhat isolated from what I recall after
reading the Apple II Redbook).

The Apple II Redbook helped me diagnose the machine somewhat, but lacks
detailed pin descriptions of the keyboard controller board itself, and only
gives the pinout of the socket that connects to the motherboard via ribbon
cable.

First of all, I'm getting strange voltages at the keyboard controller IC
(the 40 pin chip on the keyboard controller board). Here's an example:

(voltages are approximated and tended to vary a lot between one pin and
another but didn't fluctuate at all)

5 V : Pins 30
0 V : Pins 4-16,28,29
-5 V : Pins 1,2,3,33-40
 -8 V : 17-26
-13 V : Pin 27

When I pressed the 'A' key, the following voltages were observed on the 40
pin keyboard IC:
Pin 4 went from 0V to -0.8V
Pin 21 went from -8.4V to -6V
Pin 36 went from -5V to -6V

The 74LS00 next to the DM74LS04 gave some strange voltages, pins 3-5 were
around 2.5V.

The DM74LS04 gave some voltages between 3V and 4V on various pins, others
were at around -0.4V and one was at 5V

The signals B1 through B7 were giving very strange results, with voltages
varying between around 2.5V and 3.5V. Here they are specifically, with no
keys pressed:

B1: 4.08
B2: 3.46
B3: 3.49
B4: 4.15
B5: 4.14
B6: 4.07
B7: 2.83

Just for kicks, here are the other voltages on the Keyboard Connector
socket:

Pin 1: 4.94V (+5)
Pin 2: 0.17V (Strobe, I assume it's supposed to change when a key is
pressed, not sure)
Pin 3: 4.94 (Reset)
Pin 4: N/A
Pin 8: 0V
Pin 9: N/A
Pin 14: N/A
Pin 15: -13.38 (-12)
Pin 16: N/A

I checked out the power supply while it was plugged into the board and all
the voltages check out pretty nicely except for the -12V rail which was at
around -13.5V, which I'm not sure is a big deal or not. It doesn't seem to
be adjustable either.

My wild guess right now is the Keyboard Controller IC is fried, but that
doesn't really explain the strange signals on the 7400 or 7404. I made sure
the chip was socketed properly by checking each pin for continuity, and it's
fine as far as that goes. Nothing seems discolored or anything, the board
actually looks to be in really good shape other than the keyboard simply
does nothing.

I have a few of questions:

1) What do you think is wrong?
2) Where can I get a detailed pin description of the keyboard controller
board? The Apple II Redbook seems to have everything covered in great detail
except for the keyboard.

Any other advice (other than to trash it) is appreciated.

Thanks

-Rob