I've recently started designing and building circuits, and to this end, I've gotten some tools that will help me understand what's going on. I got a digital oscilloscope (Siglent SDS1052DL+) and I happened upon an old Tektronix 463A for a reasonable price. They both power on and both seem to measure pretty well. The only issue is that the last proof of calibration I have for the 463A is from 1984. I want to calibrate it, and Tektronix will calibrate it for me but it'll cost $190, assuming there aren't any broken or worn out parts that need replacement. Can I calibrate it myself and get close enough for my hobby work seeing as it seems to be working correctly, or would I be better off sending it off to Tektronix and shelling out the money to make sure it's done to the nth degree?