Kapanadze Cousin - DALLY FREE ENERGY

[verpies]

The AC or DC switch on the scope is not the cause of the problems with the signals

Are you sure you are not confusing AC input coupling with AC trigger coupling?
https://www.youtube.com/watch?v=y5aAjd9YPok

Not sure what you mean with "When the scope sees bad signals, there is no output at pin 9 or 10 of the TL494. That IS the problem"
I do not see anything like that happening, just some times where you seem to loose the sync for a short while.

Neither do I.

I'll get the scope fixed as soon as I can, but I've talked to the all the Tv repair guys in my area, and no repair shop will help me out on it.

You don't need these guys.
Just do it yourself by following TK's excellent instructions.
If you send him a still photo of the focusing knob's innards he might even highlight stuff for you.

[verpies]

is this what your looking for ?

Without the description of the probe positions and load characterization, it is difficult to say.

[Hoppy]

 
   When the scope sees bad signals, there is no output at pin 9 or 10 of the TL494.

How did you prove that?

[NickZ]

  By connecting my volt meter between the pin 16 and pin 9 or pin 10. I should get 5v out when the TL494 is working normally. But I get 0v at those pins when the scope signals are messed up. I doubt that the duty cycle or frequency pots are at fault,  but I'm not sure about that.

[AlienGrey]

  By connecting my volt meter between the pin 16 and pin 9 or pin 10. I should get 5v out when the TL494 is working normally. But I get 0v at those pins when the scope signals are messed up. I doubt that the duty cycle or frequency pots are at fault,  but I'm not sure about that.

Nick Whats on pin 3? and have you got 12v on pin 11&12 and is pin 1 & 16 at 0v ?

Also have you got 4.5 volts on pin 2, 15, 14, 13 ?    and can you vary the volts on pin 4 between pin 4.5 v and 0 ?

also put your scope probe on pin 5 and see if you have any waveform then see if you can alter it with the pot on pin 6
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