A Eurorack ribbon cable must be connected with its coloured stripe on the correct (bottom) side

Every Eurorack module powers from the bus via a ribbon cable that is polarity-sensitive. On the A-100 the cable’s coloured marking must sit at the bottom of both the module’s connector and the bus-board connector, pushed fully home and not at an angle. Getting this backwards reverses the ±12V rails: the manual warns it ‘may result in the module’s instant destruction as soon as the power is turned back on.’ Hence the check — confirm stripe orientation on both ends before restoring power — is a mandatory step, not a cosmetic one.

Examples

Install sequence detail: plug the ribbon into the module’s bus header with the coloured edge down, join the free end to the nearest bus-board slot (coloured edge down again), verify both, only then re-plug mains and test. If the module misbehaves on power-up, unplug immediately and re-check the stripe.

Assessment

Explain what the coloured stripe on a Eurorack ribbon cable indicates and what happens if a module is connected with the stripe reversed when power is applied.