Roche 91 Series - Electronics; ISE SBC Card

Roche Diagnostics April 2007
Service manual · Version 2.0 A-33
91xx pH/Electrolyte Analyzers 4 Description of modules
Description of modules
Electronics
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
develops 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 22 VDC and 12.5 VDC (16 VDC on the 9110) which
supplies the solenoids. When a solenoid is turned on, the voltage switches to 22 VDC
for 0.5 sec, then it returns to 12.5 VDC (16 VDC on the 9110).
The circuit which includes Q7 and R5 provides necessary switching for the measuring
chamber illuminator LEDs.
The following list identifies the test points, fuses and LEDs for each respective DC
supply voltage:
Test point Voltage Fuse Rating LED
TP1 +24 VDC F3 1.25 AT D3
TP2 +5 VDC F1/F2 2.0 AT/1.6 AT D1/D2
TP3 -12 VDC F4 0.3 AT D4
TP4 +12 VDC F5 0.3 AT D5
TP5 Ground
Ta bl e A -5 Voltage test points, LEDs
Test point Voltage
TP6 -8 VDC (9180/9181: -5 VDC)
TP7 +22/12 VDC
TP8 +8 VDC (9180/9181: +5 VDC)
TP9 Na
+
channel (pH channel on the 9110)
TP10 K
+
channel (not used on the 9110)
TP11 Ca
2+
/Cl
–
channel (Li
+
9180/9181 only; not used on the 9110)
TP12 Temperature
TP13 +10.000 V ref. voltage
TP14 -2.500 V ref.voltage (-2.500 V on the 9110)
TP15 Sample sensor (sample contact voltage on the 9110)
TP16 +22/12.5 VDC (+22/+16 VDC on the 9110)
Ta bl e A -6 Voltage test points