A friend emailed me last week, and said that he had some Tektronix 500-series plug-ins for me. I told him that I was happy to give them a good home. When I arrived at his house on Sunday, he had a dozen-and-a-half plug-ins for me, and also this back-breaking beast:
He said that it has a small oscillation problem, and it didn't come with any fixtures, but I am very pleased. I have several 575s (and even a 175 with the special cable), but this treasure is my first 576.