What's inside the XT90-S?

Even after a lot of googling I haven’t been able to find any pictures of the XT90-S being torn down. I wonder if the bullet in the “green slot” is a similar thing as the AS150, only smaller? I was tempted to take apart one of mine today but I only have one last. :slight_smile: Has anyone done it?


Here a somewhat look inside one.


The section circled in red is a a 5.6 Ohm resistor that limits the inrush current as it’s the first part of the connector to complete the circuit. This stops the spark from charging the capacitor. Once you push the connector all the way in that resistor is bypassed.


Right, I understand how it works. I just didn’t know how exactly it’s implemented. Well, that’s a bit disappointing. I was hoping it’s the same concept as AS150 and that I could make a smaller version of AS150 by using the XT90 anti-spark part.


I thought the AS150 resistor was on the male pin, not the female pin?

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It indeed is on the male. There’s a plastic ring on the male connector. AS150 is more “compact” in that regard as XT90 conversion will not be as clean.


Ah, good point. I didn’t think of it. I guess it would be a lot more challenging to make the “resistor ring” in the AS150 style on a female bullet.

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I actually have “make an AS150 m+f housing” on my worklist after the MR69.


Awesome, love that you guys did a tear down here.

Yeah, after I sent that I realized I misunderstood the question because I figured there was no way that you don’t know how they work… oh well, at least it’s there for others to learn if they didn’t know.

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