What was the failure rate of those vacuum tubes, that they had to be so quick & easy to replace?
I'm also curious, if the cathode was grounded to the machine frame, how dangerous was it to do work on those machines?
I'm also curious, if the cathode was grounded to the machine frame, how dangerous was it to do work on those machines?
When part performance is more unpredictable, ease of maintenance is a much bigger deal for everybody all across the price/quality range.
When ground means earth, then: The chassis isn't dangerous at all. Its potential relative to other nearby things that are also connected to earth is ~0v.
When that's used as a supply rail (like for the cathode), it still works fine. It's still tied to earth.
You don't want to put any of your dinguses betwixt that and the +150v plate rail, but... I mean. :)