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From: "anomaly3@mc.net" <anomaly3@mc.net>
Newsgroups: comp.sys.apple2
Subject: Apple IIe Manual Fault Dictionary
Date: Sun, 15 Sep 1996 21:10:05 -0500
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Apple //e Manual Fault Dictionary:
How to use this chart:
Switch on your Apple //e with no disk in any drives. Get out your logic
probe, and test the pins on each chip and note their reading. Then check
your list with the list below and compare them. Any inconsistencies
could signal a faulty chip and should be tested and/or replaced.
PIN # 1 2 3 4
CHIP 1234567890123456789012345678901234567890
----------------------------------------------------
LS125 PPPLPPLHPHPPLH
PLA PPPPPPHPHLLPPPPPPPPH
FF HHLPHPPLPPHPPPHH
Buffer LPPPPPPPPLPPPPPPPPLH
LS245 LPPPPPPPPLPPPPPPPPPH
LS374 PPPPPPPPPLPPPPPPPPPH
LS244 LPPPPPPLPLPPPPLPLPLH
Vid ROM PPPPPLPPLPPH
MMU LPPPPPPPPPPPPPHHHPHPPLPPHPPPPPPPPPPPPPPP
Processor LHPHOHPHPPPPPPPPPPPLLLLPPPPPPPPPPPOOPHPH
ShRegistr PPPPPPPLHPPPPPPH
IOU LLPPPHLLPLLHHPHOPPPPPPPPPPPHPPLLPPPPHPPP
LS10 PPPHHPLHLHHHPH
Dec/Demux PPPPPPHLHHHHHHPH
All RAMs HPPPPPPHPPPPPPPL
CD ROM HPPPPPPPPPPPPLPPPPPLPPPPPHHL
S202 LHLPPLLPPPHPLH
EF ROM HPPPPPPPPPPPPLPPPPPLPHPPPHHH
LS154 PHHHHHHHHHHLHHHHHPPPPPPH
Keybd ROM LLLHLLHHPPPLPPPPHLLPHLHH
-------- --
LS251 OLLHPOHLPPPHHHHH
RC741 PLLPPPHO
NE558 HOHHHHOHHOHLHHOH
Decoder PPPLLLLHLLLHHHLLLLLLLLLLLLLHHHLPPPPPPPPP
---------
P = Pulse
H = High
L = Low
O = No Light
Pins 1-8 & 22 & 23 on the Keyboard ROM as well as pins 6-14 on the
Decoder are readings made after "space bar" pressed.
+ These readings are taken under normal stand-by conditions.
That's all there is to it! Please do not ask what the chips themselves
do - refer to the Apple //e Technical Reference Manual, in the Hardware
Implementation section.
- Tony :-)