A: You might have a counterfeit manual. The official "Flash" meaning in the standard manual refers to the flashing LED that indicates low battery.
The term "Flash" usually refers to a community-developed firmware upgrade that allows MIDI control over the Monotron (the "Monotron MIDI Mod" or "Flash Mod"). The number "124" is often a typo or a misinterpretation of the filter chip (the Korg 35 or MS-20 filter, which has a different spec sheet). flash monotron 124 manual
The "Flash" aspect of the manual refers to how the ribbon responds. Press the ribbon at the "Low" end (left) and slide to "High" (right). The manual suggests recalibrating the ribbon by holding the power button for 5 seconds. A: You might have a counterfeit manual
A: No. The Monotron 124e (if it exists) is a European prototype. Use the standard Monotron Delay manual with the "e" addendum for power supply differences. Conclusion While the flash monotron 124 manual is a phantom name—a combination of a common mod (Flash = MIDI upgrade) and a typo (124 vs. Delay/Duo)—the resources above will give you everything you need to operate, repair, and modify your device. The number "124" is often a typo or