I would have to agree with L/Shawn on most likely a ROM/RAM issue, That probe probibally won't be of much help since you are getting a signal and not dealing with corruption, I would be curious about your logic analyzer on that point...I am working on a Fluke 9010a platform that in conjunction with an analyzer would give more flexibility and speed although a horribly expensive project...Eldorado games does nice work in my experience, although they may not touch it now that its been worked on, but might be worth a call.