Zenith Z-100 PC series Service Manual page 287

Chapter 4
Troubleshooting
CAUTION: This card contains electrostatic-sensitive devices (ESD). Exer­
cise extreme care when handling these devices to prevent damage.
General
Use of the information in this chapter assumes that one or more malfunc­
tions have been traced to the Color Video/Floppy Controller Card, and
the power on, menu selected, or disk-based diagnostics, or LEOs have
not
isolated the problem. The information provided here will supplement
the procedures provided by the built-in debugging routines of system ROM.
Refer to the "ROM Diagnostics" chapter in the Base Unit Service Module
for details on the use of these routines.
An abundance of useful information is included in this chapter which will
aid the service technician in troubleshooting problems at nearly any level
of difficulty. If problems are encountered that do not warrant the degree
of detail presented here, proceed to the general troubleshooting guide
at the end of this chapter.
Refer to Chapter 3 for Programmable Array Logic (PAL) equations and
I/O bus signal identification.
NOTE: If replacement of the gate array IC is required, a speciallC extrac­
tor must be used. The extractor part number is HE-490-230.