Ripple is within spec.
Why did I replace the capacitors?
1. It's relatively simple and cheap to replace them
2. I've had capacitor issues in other equipment. The biggest offender being the Rifa caps in my other oscilloscope
I did suspect the CRT but given that the scope works in X-Y mode that lead me down that route.
Why the pre-amp and sweep? This is where the manual lead me through the troubleshooting so far. It may be the wrong path, but it's a path I can follow to see where it leads.
