Quote:
Originally Posted by Electronic M
Is that the spec from the parts list or the schematic? Those look like parts list specs which are AC impedance NOT DC resistance. It's possible for a transformer to have a 10K AC impedance and a 500 ohm DC resistance.
What I'd do is hook up a good 4 ohm speaker and connect an audio frequency test generator to the grid of the output tube (test the tube before this test to confirm it's good) and see if it comes through to the speaker. If the the tube is good and voltages on the audio output tube are within %30 of spec and it doesn't pass audio then the transformer is bad.
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Ok, well I for sure checked all resistors in the area where I saw the smoke come from and all of the resistors tested fine yet, as for the output transformer goes what would happen if you hooked an 8 ohm speaker to a 4 ohm output transformer? I'm asking because the speaker I was using to try and test the audio output on the TV was an 8 ohm 30 watt bookshelf speaker.
UPDATE: I figured out where the smoke really came from, it came from a replacement 470 Ohm 1/2 Watt resistor I had replaced in the TV that either got really hot or got smoked because its kind of charred looking in the middle of the resistor, and the original 470 ohm 1/2 W resistor that was in there which was an old carbon composition resistor broke in half on me when I was trying to unsolder it from the old can capacitor terminal it was attached to originally when I was installing the replacement cap, (the original carbon composition resistor also looked quite charred looking as well) so I wonder if that capacitor was under spec'ed for what its intended duty was in the circuit?
12-01-2021, 05:50 PM
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