SECTION III
MICROPROCESSOR INSTALLATION
NOTE
It is necessary to perform the procedures in
this section ONLY if a field software upgrade
is performed.
3-1. GENERAL.
Four microprocessors are necessary for Premium
Vision® warning system operation. They MUST be
changed as a set. Each microprocessor in a set has a
specific function, and MUST be installed in the
correct circuit board.
The microprocessor’s part number denotes its
function. The fourth and fifth character in the part
number indicates its function as follows: CP = Con-
trol Head (Premium), RB = relay circuit board in
Amplifier/Relay Unit, AB = amplifier circuit board in
Amplifier/Relay Unit, BC = Bar Controller. Ensure
that the correct microprocessor is installed in its
corresponding circuit board.
3-2. INSTALLATION.
CAUTION
The CMOS microprocessors and the Vision’s
circuitry can be destroyed, or damaged, by
static discharge. Observe anti-static proce-
dures when installing or handling CMOS
devices or any of the Vision’s circuit boards.
A.
Control Head.
1.
Disassemble the control head as
described in the Service and Maintenance section of
the Premium Vision Hardware Installation and
Maintenance Instructions (Part No. 255274).
2.
Gently pry the microprocessor (U6) out
of its socket with a small screwdriver.
3.
See figure 3-1. Insert the new micro-
processor IC (“CP” in the part number) in the empty
socket. Ensure that the notch on the new micropro-
cessor IC is facing the same direction as the old one
(near IC4) and that all IC pins are properly inserted
in the socket—not bent under.
4.
Reassemble the control head.
B.
Amplifier/Relay Unit.
1.
Disassemble the Amplifier/Relay Unit
as described in the Service and Maintenance section
of the Premium Vision Installation and Maintenance
Instructions (Part No. 255274).
2.
Gently pry the relay circuit board
microprocessor (IC2) out of its socket with a small
screwdriver.
3-1
Figure 3-1. Control Head Microprocessor.
