:O
https://imgur.com/TUl1wO8
I had an interesting “WTF” scare over the weekend, the chassis that was working so well after the IF alignment, suddenly stopped working, no video, poor sound, only a raster with herringbone pattern.
Putting scope on point B ( output to CRT) showed strong 60 hz wave, but input on V9 grid was normal, WTF happened here?
Then noticed no bias on plate, huh? Where did the 140v go?!
Then saw that R124 was smoking... did something short?
Shut down and checked, yup, 140v, hard short to gnd, what happened? Did the replacement for C4 die? Nope, it was fine, solder fault someplace? Nope, whats going on here... wait a sec, V10! Pulled it out, short GONE! :O
The damn thing took a dump and went H-K short on me in a hard way, never saw one go this bad before, but this once again proves the rule that you should not run these un-watched :/
Who knows what could have happened, now running on another 6AU6, it seems they are pushing it to the limit in this set, some specs say cathode 100v others say 200v in relation to the heater, I know that before everything heats up it goes above 200v there, so its stressing that spec, if I saw it right.
Gotta keep an eye on that.