Sanity check fitting manual degaussing button

[big10p]

Chassis has auto degaussing circuit that fires up every time the monitor is switched on. I want to fit a button (momentary switch) to degauss the screen only when needed.

Am I right that I can fit the switch/button on either one of the wires coming from the chassis to the coil, or does the switch need to be somewhere in the circuit, prior to the PTC.

I believe it's the coil itself that draws the current through the PTC, so having the coil effectively open circuit until the button is pressed, the PTC won't heat up and do it's job until the button is pressed?

Does this sound right, or have I gone bonkers?

 

[Georgian2]

Better to be before the PTC and all that. Just like Hantarex did it.

 

[xMasterPx]

Yeah I thought if their is degaussing wires connected to the chassis you just need to wire push button or am I wrong?

 

[big10p]

Better to be before the PTC and all that. Just like Hantarex did it.
View attachment 44556

Yes, I'd prefer to fit like this, but my chassis hasn't got provision for fitting a button, like on Hantarex chassis. I think I'd have to cut traces, or something, which I don't want to do.

Here is the section of the schematic showing the simple degaussing circuit. I'd like to just fit the button on one of the coil wires, but I'm not 100% sure it'd work, and be safe. 🤔

 

[Georgian2]

Remove the coil and see if it gets any warm. It shuldn't in theory. There will always be current flowing through it but it shouldn't be much. i can't find any datasheet of the thing so I don't know the resistence values.

 

[big10p]

Remove the coil and see if it gets any warm. It shuldn't in theory. There will always be current flowing through it but it shouldn't be much. i can't find any datasheet of the thing so I don't know the resistence values.
View attachment 44558

I've got the chassis out at the moment, so can't see if the PTC gets hot without the coil plugged in. Silly me didn't think to try this before removing the chassis.

I thought the same as you, that there's current flowing through the PTC, but without the load of the coil pulling current through it, it won't get hot. I think I'm just going to have to fit a button to a coil wire, and see if it works. 🙂