Nortel DMS-10 Series Installation, Operation And Maintenance Manual page 585

Replacing EPROM integrated circuits
The BMC contains EPROM firmware routines. EPROM ICs contain
operational programming for some BMC system functions. The EPROM's
fixed memory is factory programmed with necessary control instructions.
After installation in the BMC, the EPROM always responds in the same
manner.
You may replace an EPROM IC with another EPROM IC having the same set
of programmed instructions, for example when an EPROM malfunctions or
fails. However, to change the way the BMC functions, install an EPROM IC
with different programmed instructions.
Refer to Procedure 6-35 for removal, installation, and handling precautions
when changing BMC EPROM ICs. There are two methods for changing
EPROM ICs. One method is to replace the EPROM ICs and the PEC/rel label
on the PCA. Another method is to replace the entire PCA (this is the
preferred technique).
Note: If replacing EPROM ICs, check the reference number on the PCA
diagram to make sure the right EPROM type is being used.
EPROM IC precautions
Follow these precautions when installing new or replacement EPROM ICs:
• Handle all ICs by the plastic or ceramic package, not by their metal pins.
• Do not expose the ICs to excessive force (dropping) or to large fields of
electrical or magnetic energy (power transformers, static discharge). This
mistreatment can cause partial or total EPROM memory loss.
• Make sure the UV window is completely covered.
• Work on a surface with a good electrical ground and do not wear clothes
or footwear with a high degree of synthetic materials, especially nylon.
To prevent IC damage, control or eliminate static electricity.
• The IC is designed for easy socket insertion and removal. Use only
minimum pressure since excessive force can bend or break the pins. Also,
use the specific tools for extracting and inserting ICs to avoid damaging
them.
• Use caution when handling the ICs and the PCA. Excessive force can
bend or break pins or cause hairline cracks in the copper foils.
BMC II BISYNC Operation, Administration, and Maintenance Guide BMCB001 and up
Section 060-INDP-610 Maintenance Procedures Guide 6-147