Arc OK intermitent issues on torch fire

txtrone wrote:

snowgoer540 wrote: In the diagram that post is referring to, the field power + side is wired directly to the input for arc ok. It was a mistake in the diagram.

As for resistor vs cap, it’s two different ways to skin the same cat.

Thanks! I may leave it out for now and see how things go.

Quick side question. I powered my THCAD 10 from the same 'common' PSU as the Mesa board. Is there anything wrong with that? or does it need to get power from the Mesa board?

Assuming you have a 7i96 you should take it from the encoder area of TB2. Looks like TB2 pins 6 (+5v) and pin 9 (gnd). This is for better noise immunity, I believe.

luftlupus wrote:

The above has the red wire directly connected to Vfield, that is wrong as the arc transfer relay will connect that to ground causing a short to the power supply.

luftlupus wrote:

This is correct, notice the resistors between the input and the Vfield on the red wire.

tommylight wrote:

luftlupus wrote:

The above has the red wire directly connected to Vfield, that is wrong as the arc transfer relay will connect that to ground causing a short to the power supply.

luftlupus wrote:

This is correct, notice the resistors between the input and the Vfield on the red wire.

I do. If those three resistors were replaced with one of the 1uf caps, would that work as well?

txtrone wrote: Quick side question. I powered my THCAD 10 from the same 'common' PSU as the Mesa board. Is there anything wrong with that? or does it need to get power from the Mesa board?

Nothing wrong with that, it will work either way.
And i do agree on not using any resistor or capacitor, try it without it. I never used any of those on several (count more than 20) and never had issues, but i am pretty sure it might be needed sometimes.

snowgoer540 wrote: Assuming you have a 7i96 you should take it from the encoder area of TB2. Looks like TB2 pins 6 (+5v) and pin 9 (gnd). This is for better noise immunity, I believe.

I am using the 7i76e. I connected FO+ and FO- on THCAD10 to TB3 pins 7 and 8. However I connected the 24V to 5V stepdown power to the 24V common PSU (same one the Mesa is on). I can go back and redo that part.

Black stripes over red wire, there can not be a connection as that would short the power supply when ARCOK is on.
It would be very useful if the poster of that picture corrects it to stop confusing users.