The interlocked AC power cord has another purpose besides protection from hot tube burns. Its primary purpose is to disconnect AC power from the TV when the back is removed so that the user will not get shocked from B+, or, worse, the 2nd anode voltage on the CRT.
These interlocks are not supposed to be defeated; if they are, of course, the safety feature is instantly lost, and anyone working on the TV will be doing so at their own risk. "Cheater" cords were used in the days of tube-type TVs to allow technicians to operate the set for testing purposes, although some TVs were used for years or decades (!) with cheater cords when the set's interlock cord frayed at the end that plugged into the interlock pins on the chassis. The TV may have worked with this lashup, but the safety feature of the interlock was destroyed immediately.
I would not recommend bypassing the AC interlock for any reason. These were installed on TVs and even some AC-DC radios for a reason: to prevent electric shock. There is almost always a warning on the back covers of 1950s-'60s AC-DC radios and, of course, televisions, stating that the interlock must not be defeated. To service the tubes, remove the back cover completely;
do not try to service the set with the back on. I mention this because I'm sure some folks may have tried this; i. e. they would take the screws out of the top of the back cover, leaving the bottom and/or side ones in, and try to replace bad tubes while the unit was still plugged into the wall socket and turned on.
I don't know how many people were shocked or killed this way; however, I will say this is a mighty foolish way to repair any radio or TV.
BTW: One series of radios I can think of right now that did
not have AC interlocks were the Zenith H511s (H511Y, G, W, et al) of the early 1950s. These sets were potential death traps due, at least in part, to the lack of an interlock power cord, and also because they were "hot chassis" devices, meaning one side of the AC line was connected directly to the chassis. I sometimes wonder if these sets were UL approved, or even if Underwriters' Labs was even in existence in the early '50s. If they were, I cannot see how these Zenith radios would pass inspection without an AC interlock.
