Not Fully Off when RBF is incerted

[GMW1988]

It appears that my Remove Before Flight Switch is not working correctly.
When the RBF is inserted I still am seeing some illumination in the red power LED. It is draining a little power when it should be off. I am not exactly sure why this would be happening. I do not see any other LEDs partially on when RBF is inserted.
You can see the issue in the photo with the led having a dim red color. Would this indicate a bad RBF switch or is this typical to see a little illumination when the RBF is installed?

[alanbjohnston]

I have seen this before, but rarely. Here is the current path in the schematic:

So you can see that it isn't the RBF switch that is allowing it. Instead, it is reverse current through diodes D1 and D4.

Normally, reverse leakage through diodes is very small, but these diodes are Schottky diodes. Their characteristics are that they have a very low forward voltage drop (this is good for efficiency) but they have a larger reverse current than other diodes. Your diodes must be slightly out of specification such that you can see the LED glow. Or perhaps your 220 Ohm R9 resistor is a much lower value.

So nothing is wrong with your RBF switch. If the RBF switch was failing, you would see other LEDs on the Main board illuminate, including the Pico LED, and the LED on the blue MPU6050 sensor. It just means that if your CubeSatSim sits for a week or so, the battery will gradually discharge.

If it bothers you, you could try replacing diodes D1 and D4 or increasing the resistance of R9.

Alan