This may or may not be true!
When I was doing my Radar training at RAF Locking in the 60s we had a couple of very entertaining civilian instructors. One was quite theatrical in his lectures.
I remember one of his tales as to the reason the Brits got radar working properly before the Germans was that of German thoroughness and efficiency.
He explained that as the Magnetron heated up it reached a point where it could go into thermal runaway and explode, and often did.
He went on to say that the Germans lost several of their boffins because of exploding Magnetrons in the labs. All down to the fact (?) that the heater was soldered/welded/bolted to the heater supply.
Here in Blighty, we only had crocodile clips.
Once morning while the boffins were hiding behind their blast screens waiting for the bang, Gladys came in with the tea trolley and accidentally knocked one of the croc clips off.
Drinking their tea afterwards and wondering why the big bang didn't happen, it was only then they realised the heater was only needed to get the thing to start. Once it was going it would run until its HT supplies were removed.
English tea wins the war.
At least that's what he told us - and we were only teenagers so what did we know?