HP 1740A Oscilloscope sweep problem

I purchased this scope a few years ago and occasionally it has a sweep problem. The X axis will only go to about 1 block, but occasionally the scope will work flawlessly. No problems on the Y axis. I've cleaned some of the connectors inside.

Picture of it here

https://reipooom.files.wordpress.com/2011/05/oscilloscope.jpg

I thought I fixed the problem, but it's still doing it. There is a bad connector right by the water bottle. It's hard to get to and there's the rod running through the circuit board.

I've used "DeoxIT GOLD" and moved the connectors quite a bit.

Neither of my scopes has a built-in water bottle! What on earth is that for?
Have you checked the supply rails (especially the X-axis supply rail) are stable and ok? If the scope is more than a few years old be suspicious of any supply reservoir electrolytic capacitors; they may be leaky (electrically or chemically) and/or have intermittent internal shorts which could drop the supply voltage and hence restrict the sweep.