The 545 is a tank.

A friend of mine has a 535, which will do for a tank. He used it
through his whole career at GE, and then bought it for around $20 via
the company's surplus-equipment auction a few months after he retired.

Still works, still a nice bright trace, and it's still on its original
set of tubes. He loves it.

It suffered the first malfunction in roughly forever, a few weeks ago;
the vertical gain fell off sharply. He didn't even have to move it
off of the stand to fix it - just opened up the side, exercised the
vertical gain pot a few times (it was noisy... apparently some oxide
had built up over the years), recalibrated the gain, and put the side
back on. All fixed.