SeanB i am looking for the rail you mention on schematic but cannot find it , can you pls give more details? thanks
Assuming 2465 has the same layout on the analog A1 board at 2465
B, then check the J119 header, located at the photo below, the voltages specifications & tolerances at all rails required by the scope to work properly, quoted from Tektronix 2465B service manual.
Make sure you check again at your 2465 service manual to confirm that it has the same voltage rails checking header like that.
Side note, "ideally" there is a 2nd scope to trouble shoot, so you can check the ripple as well, not just using DMM which is quite limited.
Make sure you have a huge fan blowing the "whole" board when without the case as there is no air circulation to cool off those unobtainium ICs, trust me, you don't want to them to overheat.
![](https://www.eevblog.com/forum/testgear/2467-no-power/?action=dlattach;attach=58502;image)