Advanced Instruments 3900, Service Manual

Page: 112 / 184

4CP450 Rev1
(4C35/3905 Service Manual)
Page 2 of 3
3. Remove all connections from the
harnesses that are connected to the main
control PCB (C) (J1, J2, J7-J9, J11-J13)
and the motor control PCB (D) (J1-J3, J5,
J6).
4. Pull off both boards from the two
standoffs (E).
NOTE: Serial Suffix F or greater
for 4C3 models, or Suffix A or
greater for 3900 models will
require removing two additional
screws and associated hardware
from the PCB mounting bracket.
The standoffs are located in the
upper section of the PCB
bracket. Two holes in the motor
control PCB mount into the
standoffs.
5. Remove both boards from the deck.
6. Either board can be replaced separately;
they do not need to be a matched pair. The
boards can be separated by removing the
three slotted screws and associated
hardware.
NOTE: When reassembling,
make sure that connector J4 near
the bottom of the motor control
PCB mates properly with
connector J13, near the bottom of
the main control PCB.
7. Reinstall the boards by reversing steps 1-
6, making sure that the bottom edge of
the main control PCB is captured by the
slot in the housing.
D C
J1
J2
J9 J7 J8
J1
J2
J3
D C
J1
J2
J3
J5 J6
PSI