RESONANCE EFFECTS FOR EVERYONE TO SHARE

[TinselKoala]

@gotoluc:
I also fried one MOSFET, and it was hard to troubleshoot at first. My symptoms were like yours. A single bad transistor will make the whole bridge circuit behave strangely, like shorting out one or the other whole side. On mine, I finally tracked it down by replacing each MOSFET individually with a known good unit and looking at the resulting scope trace. Easy for me since, planning ahead, I used sockets for my mosfets instead of direct soldering. (I've been playing with mosfets for a good while now.)

[gotoluc]

@Gotoluc,

>>You're beginning to be a regular Santa Claus

I was born in north Norway very close to the north Pole. So I personally know Mr. Santa. LOL

I will be looking into the wire issue. I agree that using plastic insulated wire will give some distance
between the wires. I will search my storage for such wire. It is no problem to put the secondary coil
5 mm away from the primary. You are thinking that the secondary coil will have a diameter that is 5 mm
more and sit outside the primary coil?

You are driving the IR2103's pretty hard with only 10 ohm resistors. Change to 50 ohm resistors
and add the decoupling capacitors as shown in the newest drawing. Using sockets is a good idea.

[EDIT] Attached is a proposed way to make the coils. You will have to fill in the blanks.

Groundloop.

Hi Groundloop,

yes, all the new mods will be on the new board and including sockets

thanks for the coil illustration, you are close to reading my mind

Thanks for all the non stop work

Luc

[gotoluc]

LUC
Because YOU ARE THE RIGHT STUFF
One in a zillion [billion at least]
I'm working out of state
my wife is sending Now
God bless and merry christmas
Chet

Thanks Chet, I'll let you know when I receive it.

God bless you and your family.

Luc

[gotoluc]

@gotoluc:
I also fried one MOSFET, and it was hard to troubleshoot at first. My symptoms were like yours. A single bad transistor will make the whole bridge circuit behave strangely, like shorting out one or the other whole side. On mine, I finally tracked it down by replacing each MOSFET individually with a known good unit and looking at the resulting scope trace. Easy for me since, planning ahead, I used sockets for my mosfets instead of direct soldering. (I've been playing with mosfets for a good while now.)

Hi TinselKoala,

yes sockets are defiantly needed for the MOSFET's. Maybe we even need some fuse sockets too?

Thanks for sharing.

Luc

[Groundloop]

Luc,

Look at the coil drawing again. Can you take measurement of your coil for me?
I also need to know the turns for the primary and secondary. Just update the
drawing and re-post it here.

[EDIT]  I think the new transistor switch will be more robust. Mosfets are prone to failure when used with coils.
           Regular transistors will take much more "abuse" before they break.

Groundloop.