Hi all I have an Apple IIe that has sat unused for many years. so far I've recapped the PSU (all voltages are now good) powering on gave a block pattern on screen with two or three odd colour blocks which stayed in the same position on screen when the computer is restarted. Next I replaced the 6502, now the computer responds with continual beeping and text scrolling down the screen pressing Ctrl apple apple reset stops this and displays IOU. FLAG. E5=1 3.9 the digits at the end change each time but the rest stays the same. can anyone tell me what this means. I'm more used to repairing Sinclair spectrums this is my first apple2 repair.
Jay
Hello Jay,
this indicates trouble with the IOU chip ( indication seems to be from selftest )- a custom chip that is not
availiable from regular shops....
checkout if that chip has been extracted and by reinsertion maybe a pin bent below the chip not inside the socket ?
do you have the recommended documentation on repair tasks ?
if not it´s quite usefull to pick that stuff at least from apple documentation center:
http://mirrors.apple2.org.za/Apple%20II%20Documentation%20Project/Books/
lists several books related to the IIe including material with circuitplans....
http://mirrors.apple2.org.za/Apple%20II%20Documentation%20Project/Computers/Apple%20II/Apple%20IIe/Documentation/:
offers repair guide and technical notes similar to:
http://mirrors.apple2.org.za/Apple%20II%20Documentation%20Project/Computers/Apple%20II/Apple%20IIe/Manuals/
and
http://mirrors.apple2.org.za/Apple%20II%20Documentation%20Project/Computers/Apple%20II/Apple%20IIe/Schematics/
checkout also the list at asimov:
http://mirrors.apple2.org.za/ftp.apple.asimov.net/documentation/hardware/machines/
some pictures would be usefull to complete description.....
sincerely
speedyG
Thanks for the links, I now have the computer working again. I swapped the OUI chip from my other Apple2. How easy is a replacement chip to get gold of. I'm in the uk so think it may be an issue. Are they readily available over in the states?
Hello Jay,
like i explained in my first posting the IOU chip is a CUSTOM-chip.
This means that Apple passed over productiondata of the chip to a
manufacturer and after production Apple recieved back all the chips
and all of the productiondata ! That is the reason that Manufacturer
can´t make that chip anymore ! The only chance is taking the chip
from another board if the chip is realy damaged.
Rather more often the reason for malfunction is just a bent leg or
oxydation within the socket. So it often is usefull to checkout this
possible reasons and treat for them ( cleaning the chip leg - of course
very carefull without harming the leg or the chip )
and checking if the chip will work again after reseating.
The only way nowadays to get touch of such chip is getting it from another
collector or getting touch of a mainboard where other part of the mainboard
is damaged but this chip remaining undamaged.
sincerely speedyG