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Intermec EasyCoder 501 – Service Manual Ed. 7
Chapter 17
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.
17.1 Access to CPU
Board
17. CPU Board
4 #T10 Torx Screws
4 #T10 Torx Screws
WARNING!
Disconnect the power cord
before removing the cover.
Dangerous voltage!
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.