Hello all! New to the forum (and the hobby in general).
I have recently acquired a Tektronix 455 from a friend's basement, but have mostly been using it as an absurdly oversized DC voltmeter. There is an issue with the left-hand side of the trace at higher (ie more time/div) horizontal settings on the trace, visible with a real AC signal (or even the calibration signal). Images attached. When I crank the time/div into the micro-second range, this issue goes away.
I think this is what is being described in the tek-parts/troubleshooting-scopes.pdf under "Typical Horizontal Problems"
> Problem: Compression or expansion of the sweep as it is positioned from one side to the other
> Solution: This problem is typically caused by the diode network between the bases of the amplifier. Check for leaky diodes.
I have two issues with this:
One: I don't actually know if I'm using the correct terms to describe this problem. If this issue goes by another name, I would appreciate someone letting me know... as I could easily be looking at a completely different issue.
Two: Where exactly are the "bases of the amplifier", either physically or in the circuit diagrams (I have the tek_455_clean_schematics and the manual).
EDIT: I've uploaded an animated gif to imgur showing this, as well as me moving the position knob and timebase, sorry for the shaky camera, it's on an extremely shaky extension.