SERVICE MANUAL
Medi-Therm II
REPAIR PROCEDURES
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.com P/N 10187-000 7/98
Wear a static control device connected to the chassis ground to
prevent electrostatic discharge. (See figure 5, p. 35.)
Electrostatic discharge can damage circuitry on PC boards.
The following procedures describe replacement of the power supply board. A
digital voltmeter is required.
Power Supply Board Removal (refer to figure 8, p. 67):
1.
Unplug the power cord.
2.
Disconnect the 26 conductor cable harness assembly from the power supply
board at J4.
3.
Disconnect the three cable harness connectors P5, P6, and P7.
4.
Remove the seven (7) board mounting screws.
5.
Lift board out of head.
Power Supply Board Installation (refer to figure 8, p. 67):
1.
Unplug the power cord.
2.
Place the new power supply board in head.
3.
Install seven (7) board mounting screws.
4.
Connect the three cable harness connectors P5, P6, and P7 to J3, J2, and
J1 on the power supply board.
5.
Perform a voltage check of the power supply board. Do not use the board
or connect it to the control/display board if the voltages are incorrect.
NOTE: To prevent an accidental short circuit, connect voltmeter
leads while the machine is off.
With the 26 conductor cable harness assembly disconnected from the
power supply board and the machine on, measure for the following
voltages at the following board locations (see figure 23, p. 84):
DVM
DVM
Common
+ Lead
Voltage
to Pin
to Pin
Reading
Q7
1
3
-12 ± 0.5V
Q6
2
3
+12 ± 0.5V
C16
–
+
+5.3 ± 0.3V
6.
Turn machine off.
7.
Connect the 26 conductor cable assembly.
8.
Perform the
FUNCTIONAL CHECK AND SAFETY INSPECTION
(section 7.3)
CAUTION
9.2
REPLACING THE
POWER SUPPLY
BOARD
60
