Teledyne 4700 Serivce Manual page 91

Table 4-2 CPU Board Functional Tests (Continued)
Function Command
Test RAM T22
Loads and reads back the four 16-bit words
FFFF, 0000, a5a5, and 5a5a in RAM.
Test ROM T23
Performs a Checksum test.
Test display T24
Solid boxes march across screen, then alphabet
characters on each line. Observe the display to
determine pass or fail.
Additional testing: Clock Speed
In the test mode, the master clock output pin is enabled to allow measurement of the clock frequency. Exiting test
mode disables this pin. Additionally, the duty-cycled pulses to the heater resistor essentially stop (reduced to 0.01%)
during TEST mode. These pulses also are restored when TEST mode is exited.
Measure the clock speed MCKO on TP6.
8 MHz signal (125 nsec period).
Test pump drive T26
forward
Optical sensor connections:
P8-1 = +power to LED, P8-2 = –power to LED,
P8-3 = +3.3V to sensor, P8-4 = signal from
sensor.
Connect either the actual motor or a simulator
at (P10-1(+) and P10-2(-)). Activate the pump
drive output in forward mode.
Test pump drive T27
reverse
Optical sensor connections:
P8-1 = +power to LED, P8-2 = –power to LED,
P8-3 = +3.3V to sensor, P8-4 = signal from
sensor.
Connect either the actual motor or a simulator
at (P10-1(+) and P10-2(-)). Activate the pump
drive output in forward mode.
Test liquid detector T29
This test requires a resistor divider network
powered by the 3.3V analog voltage of the
board and grounded at analog ground
(P7-3).The network should be divided to provide
750mV to the liquid detector input (P7-2).
Additional testing: Pump interlock
Close the pump interlock input by shorting P9-1 and P9-3. Perform tests T26 and T27; the pump should pass. Open
the short. The pump should fail the tests.
Test distributor drive T28
The test commands the distributor to move to
bottle position 24.
4700 Refrigerated Sampler Service Guide
Section 4 CPU and Power Supply
Results
Electronics
Returns OK or NOT_OK
Returns OK or NOT_OK
Returns OK to indicate completion
Pump
On/off ratio should be between 0.8 and
1.25.
If the optical sensor sees motion, the test
returns On/Off ratio and then OK;
If not, the test returns NOT_OK
On/off ratio should be between 0.8 and
1.25.
If the optical sensor sees motion, the test
returns On/Off ratio and then OK;
If not, the test returns NOT_OK
The test will return 20 readings of the
analog voltage on P7-2 (750mV).
Returns OK to indicate completion
Distributor
Returns OK or NOT_OK
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