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I have a RAMPS 1.6 board. After soldering my stepper drivers, I probed them for bridging and found a short where none should be. Digging deaper into it, my multimeter shows continuity between the 12V +/- connectors (on occasion).

I have scanned the whole board repeatedly for solder bridges, but could not find any. Are there any known weaknesses that I should look for or any specific place I should look at to repair it?

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  • $\begingroup$ Can you switch your multi meter into Resistance measurement mode and report the measured resistance between 12V+ and 12V - $\endgroup$
    – Lars Pötter
    Jun 4, 2019 at 18:55

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Your multimeter showing continuity doesn't necessarily mean there is a short.

All your multimeter is doing is applying a small voltage and then, if the current that flows is over a certain threshold, reporting that there is continuity.

The components (stepper drivers, microprocessor) on the board, draw current. That's normal. The current draw might be enough for your multimeter to report continuity. Because the multimeter is only using a small voltage to test (and not the required 12V), the current draw may be intermittent (not enough voltage for the microprocessor to actually start working), and capacitors getting (dis-)charged may also affect things.

The multimeter not reporting continuity is a guarantee of no short. However, the multimeter reporting continuity does not mean there is a short. The only way to find out is to apply 12V. If you use a current-limited power supply the possibility of damage if there is a short circuit is limited.

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