Service manual
Testing the Power Supply
4-20
8. Turn the cardiograph On by pressing .
9. Measure SW+5V between ground and the point marked SW+5V. It should read +5
Vdc. Its presence confirms the proper operation of the switched 5 volt regulator and
boost regulator.
10. Turn the cardiograph to Standby.
11. Unplug the cardiograph from AC power.
12. Look on the first page of the Extended Self-test printout and verify that the printhead
voltage is approximately 26.1 Vdc. If the voltage is correct then the power supply test
is complete and the cardiograph may be reassembled. If the voltage is incorrect or the
printer is inoperative then proceed with the following steps.
13. Disconnect the keyboard connector from J201. Place the upper case on top of the bot-
tom case assembly. Turn the unit bottom-side up.
14. Install the battery and turn the unit top-side up.
15. Remove the upper case.
16. Connect the keyboard cable to J201.
17. Turn the cardiograph On.
18. Connect one end of a jumper wire with grabber clips to pin 1 of VR5. The jumper
wire is now connected to +5V. Connect the other end to the lead of R37. The other
end is now connected to PPWRON.
19. Measure VPRINT between ground and the point marked VPRINT. It should read
approximately 26.1 V DC. Its presence confirms the proper operation of the printing
supply circuit.
20. Remove the jumper wire.
21. Turn the cardiograph to Standby.
22. Close the top cover assembly.
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