GE MAC 3500, Service Manual, Page: 63 / 180

Revision L
MAC™ 3500 Resting ECG Analysis System 4-23

2021337-036
Troubleshooting: Diagnostic Tests

DCOut Loopback Test . This involves connecting the DC Outputs to the DC
Inputs. The test sends all possible values out the DC Outputs and confirms that
correct values are read from the DC Inputs. A pass/fail result is displayed at the
end of the test.
To run the test, connect DCOut1 (pin2) to Analog Input (pin 7) and DCOut2
(pin 6) to Analog Input (pin 9).
NOTE
If test fails you may need to replace the CPU board.

(See “Main CPU Board Replacement” on page 5-22.)

ECGOut/QRSTrigger Loopback Test . This involves connecting the ECG Output
and TTL Trigger Output to the DC Inputs. The test sends all possible values out
the ECG Output and a square wave out the TTL Trigger Output. It confirms that
correct values are read from the DC Inputs. A pass/fail result is displayed at the
end of the test. If test fails you may need to replace the CPU board. (See
“Main
CPU Board Replacement” on page 5-22.)
31A
PIN Name Pin Name
1 +12v 6 DC Output 2
2 DC Output 1 7 DC Input 1
3 *
TTL Trigger Output
* also called “QRS Trigger”
8 ECG Output
4 Ground 9 DC Input 2
5 Ground
1
6
5
9
33A