Why do KOSO speedometer for mio FAIL?

Yamaha Mio scooter probably has the most aftermarket parts available nationwide, from adds-on to performance parts. For beautification, there is the so called digital speedometer made by KOSO Taiwan, which was primarily made with the particular model of Yamaha Scooter available all though out ASIA pacific region. It is a plug and play accessory that will replace the OEM speedometer panel of the said scooter. While it has been said for being plug and play, it will use the existing original wiring system of the scooter, but then why many users seems to have problems that their purchased KOSO speedometer fail after installation?

COMPARISON

First, let us compare the OEM or standard mio speedometer Vs. Koso speedometer.

Left picture is the standard OEM speedometer. From the looks of it, you'll be able to distinguished it as analog speedometer due to dial meter of the odometer, and the fuel gauge meter. All indicators of this type is utilizing bulb, a wedge type of bulb that illuminates the panel back light. It has no circuitry board..it only consist of moving coil assembly and no complex circuit that do not need attention of a fail DC. When indicator fails, just remove the bulb and replace it with the right wattage and they will work again. Even without the main electrical fuse of the scooter will not harm this kind of speedometer. BUT!!!

now let us take a look of the so called KOSO digital speedometer for MIO

From the word itself DIGITAL. displaying a readout in numerical digits rather than by a pointer or hands on a dial. It has complex circuitry, and when we say complex, there is an MCU that performs the analog signal that are converter to digital to display the right data onto the LCD display. When there is a circuit involve, there are certain values of voltage that must be precise in order for those components to work properly, they have their minimum and maximum voltage threshold to work properly, like switching the lights, displaying the correct image, etc etc etc.