I would indeed test that but I am stuck with a ~10nS rise time output here. I suppose it's a good excuse to build a Jim Williams pulse generator...
I must admit when I cracked it open, the timebase did leave me a bit "whaaat?" in this case because the board wobbles when you turn the knob. I will probably leave it be for now and just buy another 1740A to keep in the cupboard just in case
![Smiley :)](https://www.eevblog.com/forum/Smileys/default/smiley.gif)
However looking at this, it's museum grade inside. The cal seals were still present from '84. The only thing showing any wear or damage is the feet and I don't think I've ever seen scope feet that aren't knackered. It'll get some makeshift ones from whatever I can find on RS.
Alas no 485 has ever come my way for a price I'd pay or I'd snap it up instantly
![Sad :(](https://www.eevblog.com/forum/Smileys/default/sad.gif)
... still slightly regretting selling my 475 which was in mint condition a couple of years ago. That was second best to the 485.