Access To Cpu Board - Intermec EasyCoder 501 Service Manual

17. CPU Board
17.1 Access to CPU
Board
WARNING!
Disconnect the power cord
before removing the cover.
Dangerous voltage!
4 #T10 Torx Screws
CAUTION!
When replacing circuits on the CPU
Board, make sure never to expose them
to electrostatic discharges (ESD).
This applies particularly to (C)MOS
[(complementary) metal oxide semi-
conductors], like RAM, PROM, GAL,
and to the printhead. Electrostatic dis-
charges destroy the insulating metal
oxide between electric layers, thus
reducing the lifetime of a circuit dra-
matically. Therefore handle components
only at an ESD-secured workbench
fi tted with table carpet and anti-electro-
static wrist straps grounded to an ESD
inlet.
Intermec EasyCoder 501 – Service Manual Ed. 7
The CPU board is situated in the electronics compartment on the
left side of the printer's center section. To gain access to the elec-
tronics compartment, proceed as follows:
• Switch off the printer and disconnect the power cord. The CPU
board contains power supply circuits with dangerous voltage.
• Remove the four #T10 Torx screws situated along the lower
edge of the cover plate as indicated on the illustration below.
• Open the right-hand door and remove the four #T10 Torx
screws at the top of the cover plate.
• Remove the cover plate.
• Reassemble in reverse order.
Before touching the CPU board, carefully read the following
instructions:
• A red LED at the upper front corner of the CPU board indicates
when the power is on.
• Take precautions to prevent electrostatic discharge, see note.
• Keep in mind that the RAMs and the clock circuit are battery
backed-up. Therefore, there is a risk of short-circuit if any con-
ductive tools are used on the CPU board.
• When adding or replacing any socket-mounted circuits, make
sure that their "front" markings are heading in the direction
indicated by the components diagram in Chapter 17.5.
Chapter 17
4 #T10 Torx Screws
121