On some presets I cannot hear any Chorus or modulation, even if the MODULATION block is ON
You are probably on a preset with SERIAL-2 routing and DELAY block is OFF. Serial-2 routing will insert the modulation block on the delays repeat. So if the delay is bypassed and you activate the mod block, you will not hear any modulation. To solve the problem use a SERIAL, SEMI-PARALLEL or PARALLEL routing.