A lil' update on this thing: I've attempted an alignment. However, it needs help. The oscillation is generated using an RC timing circuit. The R values are selected with the digit dial at the front, the C using the frequency ranges.
The resistors there are within spec for what their respective bands call for, but the service manual says they are handpicked. And handpicked they have to be for this to be somewhat accurate. And they drifted enough for it to be woefully off. I can get at best 2 digits accuracy when it should give me 3.

That's R912. Should be 270 Ohms

0.1% resistors cost about 50 cents each. Means it would cost me north of 15€ to replace those resistors. Guess I will be buying 1% resistors instead, but 100 of each value and then grade them and pick the best ones to get the accuracy needed.

You know, as cool as vintage test equipment is, it can be a real pain in the neck to keep running. That noise is internal to the scope. Guess the Philips THT electrolytics want replacing too now.