Service manual
MODIFICATIONS TO THE ARX 800A TRUNKING LOGIC
CONTROLLER
All
ARX 800A Trunking Logic Controllers produced
as
of 7/6/89 include
an
additional high pass
filter (HPF). This hybrid HPF
(part#
BDEY0334001) corrects a low speed data noise problem that
occurs when the ARX 800A is used with the ARX 780 Telephone Interconnect.
The schematics
and board view of the
ARX
SODA
in
this manual
DO
NOT show this modification.
If
you are using an ARX 800A Trunking Logic Controller that was produced before 7/6/89, modify
it
as
follows:
1.
Carefully remove IC19
(UC11
05) from the PCB.
2.
Solder an insulate wire to pin 7 of IC19.
3. Solder an insulated wire into the hole
in
the PCB that pin 7 of IC19 went into.
4.
Carefully replace IC19
in
the PCB. Have IC19 rise slightly off the PCB to avoid shorting the two
wires.
5.
Connect the wire from the PCB
to
pin 4 of the hybrid HPF.
6.
Connect the wire coming from pin 7 of IC19
to
pin 2 of the hybrid HPF.
7. Connect
an
insulated wire from
pin
1 of the hybrid HPF to pin 8 of IC25 (+Vee).
8.
Connect an insulated wire from
pin
3 of the hybrid HPF to pin 4 of IC25 (Gnd).
Make sure to check the ARX 780 Telephone Interconnect for proper deviation and interfacing to
the telephone lines. Refer to the ARX 780 service manual for the alignment procedure.
1/1/90
Page
48
MRS 904