Instruction manual

190
Chapter 5 Section I: Replacement Procedures
Resistors, Terminating
For parallel interface configurations, the printer is equipped with 470 ohm pull-
up terminating resistors and 1K ohm pull-down terminating resistors on the
controller board. These are suitable for most applications. (See Figure 27,
page 191.)
If the standard terminating resistor pack is not compatible with the particular
interface driver requirements of the host computer, other values of pull-up and
pull-down resistors may be required. 220 Ohm pull-up and 330 Ohm pull-
down alternate terminating resistors are provided with the printer. If you install
the 220 Ohm pull-up resistor, you must also install the 330 Ohm pull-down
resistor. Possible terminating resistor combinations are shown below.
Removal
CAUTION To prevent electrostatic damage to electronic components, always wear
a properly grounded static wrist strap when you handle circuit boards.
1. Prepare the printer for maintenance (page 106).
2. Cabinet Models: Remove the paper path (page 177).
Pedestal Models: Remove the top cover assembly (page 161).
3. Locate the terminating resistor packs. (See Figure 27, page 191.)
4. Using a chip puller, remove the resistor packs.
Installation
CAUTION To prevent electrostatic damage to electronic components, always wear
a properly grounded static wrist strap when you handle circuit boards.
1. Using a chip installation tool, install the resistor packs in the correct
socket. (See Figure 27, page 191.)
2. Cabinet Models: Install the paper path (page 177).
Pedestal Models: Install the top cover assembly (page 161).
3. Return the printer to normal operation (page 107).
Configuration RP1 (Pull-Up) RP2 (Pull-Down)
Factory Default 470 Ohm 1K Ohm
Alternate 1 220 Ohm 330 Ohm
Alternate 2 1K Ohm None