UPDATE - May 2025 I've recently revisited this theme and found a more robust solution which has better stability in terms of timing. This involves using a photo coupler to isolate the external clock signal from the Casiotone's circuit. The approach shown below is still viable but I'll endeavour to post the updated method soon. ====================================== The older Casiotone keyboards with analogue circuitry can generally be modified to accept external clock signals for synchronising their rhythms to other equipment - but there are a few caveats: 1. there are various Casiotone 'families' based on different chipsets and implementations. This means there's no standard way to do this across all models and even models that share the same CPU might be programmed differently. For example, with an external clock signal, the CT-310 and the MT-65 sync at the same tempo while the MT-86 plays at half their speed. 2. the mod outlined below might not deliver a ...