Kapanadze Cousin - DALLY FREE ENERGY

[itsu]

Nick,

i have to agree with both Hoppy and verpies.

It just looks like you loose the sync, but you have to try to fix the scope first.
Then like verpies mention put it to DC coupling as it is now in AC coupling for both probes.

If you loose the sync again while turning some pots, just adjust the triggering level point to obtain a new steady signal (you might need to increase the vertical settings)

You show just scoping the TL494 outputs, please when you have fixed the scope, also try to probe the gates and the drains and even a combination of gate / drain one by one.

The new filters (chokes / caps) look great and should filter out RF to a great deal.

Regards Itsu

[verpies]

The new filters (chokes / caps) look great and should filter out RF to a great deal.

The electrolytic caps might be inadequate for filtering higher frequencies.
If scoping across these caps shows HF components, then soldering some lower capacity film capacitors across them will remedy that.

[AlienGrey]

The electrolytic caps might be inadequate for filtering higher frequencies.
If scoping across these caps shows HF components, then soldering some lower capacity film capacitors across them will remedy that.

is this what your looking for ?

Before any bright spark asks me for the secret, I have two other modules and they won't play along active components are in sockets and it's not them but appears to be related to the driver output stage and torrid capacitor and grenade, with no EHT stage or load supply voltage, is 14.5v at 4 Amps. at 17.8khz approx

[NickZ]

  Verpies, Hoopy, and Itsu:
  Ok, thanks for your comments.
  The AC or DC switch on the scope is not the cause of the problems with the signals, as I've tried them both ways, and the problem persists, just exactly the same.
   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. But, the scope is working for what I need it to do, at this point. Which is to get the TL board working without messing up the signals when turning the pots. It's blurry but it's working well otherwise. Sorry it bothers you, it bothers me too.
   When the scope sees bad signals, there is no output at pin 9 or 10 of the TL494. That IS the problem. Which I've had even from the start of this board. So, I doubt that it's the trim pots causing it. But, I'll replace them (again) anyway, just to be sure, as I don't know what more to try.
  I've replaced just about everything, several times, including the TL494 IC, UC4420 fet drivers, resistors, caps, etz...
 
   The filter caps should be doing their job, as well. As I have not only the bigger electrolytic 1000uf caps, plus a 104j caps, on the both sides of the voltage regulators. As well as a 0.1uf caps between the positive and negative of the TL494 IC, and also on the UC4420 fet driver circuit. So, that part should be ok. I hope.

   The scope signal can get much worse than what I showed on that last video. On the video they were working fairly well, compared to what they do at other times.
   I will replace both trim pots, the (20k and the 50k), just in case that they are damaged. I have tested the pots out of the circuit and they were working well throughout their ranges, though. We'll see if that takes care of the issues, but somehow, I doubt it.
  I did see something similar happening on one of Itsu's videos, and I thought I'd ask to see if anyone else has experienced that same kind of thing happening on their device.

[itsu]

Nick,

to me, the video shows a perfectly good working TL494.
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.

So you need to make it more clear to us what exactly is the problem.
We do know now that as you are running without the yoke, its a problem in the basics of the TL494 circuit.

I always had to work with the max. duty cycle (45%) for the yoke to present the correct resonance signal, so keep it at max (45%).

Make sure to put / have a 0.1uF ceramic cap directly across the TL494 (and uc4420) plus / minus leads, preferrable directly across the chips leads.

Itsu