Kapanadze Cousin - DALLY FREE ENERGY

[itsu]

Nick,

So your 15V regulator for the MOSFET drivers is defective, that part i understand, so replace it.

The rest of your info is not making much sense to me.

first of all, you mean TC4420 for the drivers, as no UC4420 exists, and then you talk about signals at the drain, no drain signals, gate signals are clean but firing at the same time
duty cycle going to 100% etc.

Concerning the screenshots, they show the drain signals? (thats what they are called),
but CH1 is at 2V @ 10x = 20V/div. meaning a square wave signal of about 60V??
CH2 is at 5V @ 1x = 5V/div. meaning a square wave signal of about 12.5V??

Why is CH1 at AC coupled and CH2 DC coupled?

The sequence of these drain signals look OK to me, the upper drain is active (pulling the voltage to ground) when the lower drain is inactive (voltage high).
Duty cycle looks something like 33% (on the gates). This way your MOSFETs should be OK.
Frequency looks very low still (830Hz)

Itsu

[AlienGrey]

  Hoppy:
  I've got two filter caps at both the input as well as at the output of the 15v regulator. They are the ones that are recommended by Ruslan's circuit diagram. The 1000uf and also the smaller 104J capacitors, on each side of the regulator. But, if I disconnect the output side of the regulator, I get 24v on the input of the regulator, but no voltage on the output side of the regulator. So, it's gone bad.

  Funny thing though, last night with only 4.2 volts somehow getting to the UC4420 drivers, possibly somehow through the ground side of the regulator, which was still connect up, I WAS getting a square wave signal at the drains. First time.  But, somehow connecting the drivers inputs up to 12v from a battery, I get no drain signals at the drains.
Plus now, not only are the gate signals clean, but they are back to the gates firing at the same time. And the duty cycle going to 100%. So, get that... for a learning curve to unwind.

Try inverting one of the winding going from + volts to the drain.

[TinselKoala]

Nick, it is very difficult to interpret your scope "Drain" signals if the channel V/div, input coupling, and probe switch settings are different between the channels.

Please repeat the "Drain" shot with all scope settings the same for both channels (and check the switch on the probe itself as well.) DC coupled, v/div the same for both channels, probe switches on "10x", probe tips at mosfet Drain pins or mosfet tabs (which are also connected to the Drains), probe ground references at Source, ie common negative rail. (Also be quite sure that the mosfet heatsinks do not short the two mosfet Drains together.)

During some time when both Gate signals are firing simultaneously, can you please check the Voltage on the Pin 13 of the 494? This is the "steering" pin. If it sees "ground" or zero voltage, it tells the chip to fire both outputs simultaneously. For normal Push-Pull or alternate output firing, this Pin 13 must see the Vref voltage which appears on Pin 14 from the chip's internal voltage regulator.

Personally, I think it is time to consider scrapping the circuitboard you are using now, and building another unit from scratch, incorporating what you've learned and making the various connections easier to see, understand and work with. And do get your hands on some 8-pin DIP TC4420 driver chips!

[Hoppy]

Nick,

Please take TK's advice and rebuild your board from scratch. Experience tells me that by now with all the alterations you have made, your board must be very messy and a messy board is a breeding place for connection faults.

[NickZ]

   Well, sorry guys, but I'm not in position to start from scratch, as all I've been doing is starting from scratch, for the last two months or so. The board is not so bad as to chuck it.
   It's not the board at fault, but the builder of it, instead. I could make the same errors on another board if I don't work out what's wrong, at this point.
   
   Don't worry about not being able to see it all clearly, for now. It's a prototype, and I'll figure it all out in time.
The main problem as always, is getting all the needed parts.

  There's a reason that the scope knobs settings are that way, (in different positions). As one of the TL494 channels has higher amplitude than the other, or at least it did. And yes, TK, one of the scope probes was set on 1X and the other on 10X. I corrected that. I'll place the knobs the same in my next pic. No need to try to figure out that last signal. I think that I got it.
  But, even without the 12v or 15v going to the TC4420 drivers, they will give a signal to the drains. Even on as little input as 1.8v. And now when I give these same TC drivers 12v from a battery it cuts off that 1.8v signal it was getting before to the drains. So, I get nothing at the drains when the drivers get the normal 12 or 15v input. But, I do get drain signals, on just the 1.8v input to the drivers, which they get from somewhere.
Just trying to get a grasp on all this. Makes no sense to me, either. But, there's a reason for everything.