7.
Given the following symptom, use the troubleshooting chart (figure 2-4) and refer to
the defibrillator schematic in Appendix G to isolate the cause of the malfunction.
SYMPTOM: The monitor works perfectly, but the defibrillator charges continuously
without ever reaching a full charge.
SITUATION: On
the oscilloscope, you
see that U3
pins 4
and 6
have square wave
outputs, 180 degrees out of phase, with alternating 5 and 10 microsecond pulses. With
the oscilloscope still referenced to ground, you read the voltage at U4 pin 2. It reads only
10vdc. You followed the circuit (Appendix G) back to CR6 and CR7, and you read 10vdc
on the cathode of CR6, but zero v on the cathode CR7. Which item is open and needs to
be replaced?
a. U4 pin 2.
b. U3 pin 4.
c.
CR6.
d. CR7.
8.
You have isolated a malfunction to a defective recorder, and you are replacing the
recorder. After you disconnect the chart recorder plug, you should:
a. Remove the chart recorder.
b. Loosen the two rear screws to function as a hinge for easy access to the circuit
boards.
c.
Remove the four chassis mounting screws holding the chart recorder into the
chassis brace.
d. Remove the two front screws holding the base to the monitor chassis.
Check Your Answers on Next Page
MD0362
2-59