Agilent 7890A GC external event - no change in signal with valve activation

I’m trying to configure the external event connectors #5 (pin 1 and 3) and #6 (pin 2 and 4) to trigger a DAQ. I’m currently testing the flow logging but I am stumped. I have an 8 pin mini DIN from external event output with wires corresponding to pins 2 and 4 (confirmed with multimeter) connected to a BNC test adaptor. A BNC cable is then run from this connector to the DAQ device. Other GCs are able to send a 24 V signal to the DAQ with no issue.

Whether the corresponding valve is on or off, the voltage is constant and does not drop when valve is off. What’s more is that the signal is not the 24 V as expected, but instead delivers anywhere from 25-28V. This voltage range is also seen on valves #1-4 but there are no issues with these. Adding a load seems to rectify the problem but causes an overcurrent error: “Valve 6 overcurrent shut down”.

Any ideas on how to rectify this issue would be very helpful.

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