Chapter 3-Installation for 800XL
Locate Important Integrated Circuits (800XL)
ANTIC - U7 Also labeled either C012296 or C021697. This is the
second 40 pin IC from the left at the front of the PCB. The part
number of this IC determines whether you connect a jumper wire
to point 'C' (or not) on RAMBO XL and also how you set JP3.
PIA - U23 Also labeled C014795 or 6520. This is located two ICs to
the right of ANTIC in the 800XL. This should be socketed since we
will need to bend up five pins and solder the ribbon cable to them.
Memory Decoder IC we are replacing - U27 Also labeled 74LS158.
This is a 16 pin IC. U27 is to the left of ANTIC and several ICs
above it. If this IC is soldered directly to the PCB (without a socket)
then you must carefully unsolder it and replace it with a 16 pin
socket.
RAM Chips - the 800XL has them labeled U9-U16 and they are
along the left hand side of the PCB. These should all be in sockets.
If not, you must unsolder these ICs and replace them with sockets.
Check Jumpers and Jumper Block Settings on the RAMBO XL
Board
See the following table (table 1) to determine which jumpers you
need to run and how to set the jumper blocks for your computer.
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