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4.3 Electronics
4.3.1 ISE SBC Card
Power Circuits
Power is supplied to this circuit board through connector JP3 from the power
supply assembly. Test points are provided to measure supply voltages, and light
emitting diodes D1 through D5 are turned on to indicate each supply voltage
present on the card. Since each LED is connected in series after the fuse, a blown
fuse results in the respective LED turned off.
Four additional voltage regulator circuits are mounted on the ISE SBC II Card. IC
U2 and IC U3 provide -8 VDC and +8 VDC (9180/9181: -5 VDC and +5 VDC)
and are used to provide the supply voltages for the analog circuitry. IC U1 devel-
ops the supply voltage used to operate the peristaltic pump and provide either +10
VDC or +22 VDC. The +22 VDC is supplied only for the FAST speed and +10
VDC is used for all other pump speeds. Signal FAST/SLOW determines which
supply voltage is selected.
U5 switches the voltage between 22VDC and 12.5 VDC which supplies the
solenoids. When a solenoid is turned on, the voltage switches to 22VDC for 0.5
sec, then it returns to 12.5 VDC.
The circuit which includes Q7 and R5 provides necessary switching for the measur-
ing chamber illuminator LED’s.
The following list identifies the test points, fuses and LED’s for each respective DC
supply voltage:
Test Point Voltage Fuse Rating LED
TP1 +24 VDC F3 D3
TP2 +5 VDC F1/F2 D1/D2
TP3 -12 VDC F4 D4
TP4 +12 VDC F5 D5
TP5 Ground
TP6 -8 VDC (9180/9181: -5 VDC)
TP7 +22/12 VDC
TP8 +8 VDC (9180/9181: +5 VDC)
TP9 Na
+
Channel
TP10 K
+
Channel
TP11 Ca
++
/Cl
-
Channel (Li
+
9180/9181 only)
TP12 Temperature
TP13 +10.000 V Ref. Voltage
TP14 -2.500 VRef. Voltage
TP15 Sample Sensor
TP16 +22/12.5VDC
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