180AS KVM Troubleshooting Help

Last week, our PowerEdge 180AS KVM seemingly decided to stop working normally. It was functioning just fine on a tiered setup and then after turning it off and moving power it no longer works as it should.

I've created a simple setup with an Optiplex workstation and a SIP connector to try and reproduce and fix the problems. The symptoms are as follows:

1. If I plug everything into the workstation and the KVM, the yellow indicator light on the KVM flashes once every 3 seconds in tandem with horizontal lines on the monitor.
2. If I remove the local video source (the monitor to the KVM connection) the yellow indicator light remains solid.
3. If I plug the monitor back in, the symptoms in step 1 return.

After 5 hours of trial and error I was able to successfully load the latest firmware. The software update said it completed, but I really have no way of knowing for sure.

Any ideas with what may be the problem?