Greetings to all. I am a very new user of this forum, so please excuse any missteps. I have an old Gould OS255 scope which, with the exception of some very noisy switches and pots, seems to work quite well. There is a relatively minor issue with the trace. If the trace is positioned near the top of the screen it is quite level. Positioned mid-screen there is a downward dip at the left. Positioned at the bottom of the screen the trace dips at the right. This behaviour is present on both channels and is seen regardless of input (even when set to ground). Am I liable to be looking at a CRT power supply issue, or something a bit more insidious? I am not particularly familiar with scope innards. I'm hoping to use it as a backup to my main scope, a Tek 442, which works perfectly when in a good mood (maybe a later post...) Appreciate any suggestions. Thanks, Neil.