I seem to be starting, last week picked up my first, a B&K Precision 2120 20Mhz, full analog. I brought it home after as thorough of a check as I could without anything but a constant power supply and a digital multimeter with a frequency counter. I started using it that night and noticed something weird, the traces would drift down the screen as I was trying to use it. I downloaded the service manual and looked around, I found the vertical calibration circuit diagram and started poking around, but everything seemed to be fine. I asked here and someone pointed me to the vertical preamp circuit, I found some flaky capacitors and a few bad diodes, tested more with a hair dryer pointed at the board, more of the capacitors started breaking down. So I ordered some parts from Mouser to fix it, all new capacitors and some diodes. I decided I needed a working oscilloscope in the mean time until the parts came, it can be hard to fix an oscilloscope without a working oscilloscope.
I went back to Craigslist, I knew there were some Tektronix scopes on there for a reasonable price, but the guy was unresponsive before. Those turned out to be duds, he contacted me and sent me pictures, one wasn't a 100Mhz Tektronix at all, it was a Temna 60Mhz, so I decided it wasn't worth the drive.
I saw a new one listed, a Tektronix 2221A, an old CRT digital storage scope. He had good pictures, showing that it at least displayed something, he wanted $120. I setup a meeting for this afternoon to look at it, it was 10 minutes from my house. He had no probes, so I grabbed my B&K's probes and went over. I get there and he had it ready, so I plug it in and let it warm up for at least 10 minutes. I play with the controls and get the probe calibration waves going. I started messing with the digital storage stuff and it was immediately clear there was a problem. The text is all smeared around for some reason. Though, I noticed if I leave all of that stuff turned off, it works quite well as a full analog scope and the traces were stable for at least an hour. It also had some flaky knobs, which if you hold them right, they will work fine and I could live with it. I talked him down to $40 and took it home, I figure I could sell it for parts for at least that if something major did pop up.
The parts to fix the B&K are here and the scope is warmed up, going to get out the soldering and desoldering irons and get that running again.
Oh, and the Rigol is still on the list to get soon.
So yeah, I think it is starting.