Troubleshooting & Maintenance
Boot EPROM
4-9
Boot EPROM
The PC3x uses a 32 pin EPROM located at U4 to store the boot up information for the CPU.
Removing the EPROM
1. Place the PC3x upside down on a
fl
at protected surface.
2. Remove the seven screws that secure the access panel and set it safely aside.
3. Use an AMP 822154-1 extraction tool to remove the EPROM.
Warning
: Typically, you would insert the tool at one corner to lift the EPROM then repeat the
process at the other corner. However, because of the proximity between the U4 socket and the
keyboard, this is not possible.
4. Insert the thin, straight end of the tool into the extraction hole closest to the xD/Daughter
Board.
5. Slightly, lift up the corner of the EPROM.
Warning
: While the extraction tool is inserted into the extraction hole, do not to allow the tool to
move from side to side. Doing so could cause damage to the EPROM or the socket.
6. Remove the tool.
7. Insert the curved end of the tool into the same extraction hole.
8. To remove the EPROM, slide the tool farther toward the center of the EPROM so that it
will lift straight up and out of the socket.
Caution
: Place a
fi
nger on top of the EPROM so that it does not pop out suddenly either
damaging it or landing in an inaccessible area.
Replacing the EPROM
1. Position the EPROM over the socket. Be sure the beveled corner of the EPROM is correctly
positioned over the corresponding corner of the socket.
Caution
: If you need to reposition the EPROM, always lift it up from the socket
fi
rst.
2. Gently press the center of the EPROM into the socket and verify that the EPROM is
correctly positioned. Using too much pressure, may cause the PC board to
fl
ex and
damage the delicate solder connections under the MARA ICs.
3. Position the access panel on the bottom enclosure and install the seven
screws to secure it.
