Triac based Dimmer control

Hi,

You need to provide complete informations:
* what optocouplertriac?
* what exact load (resistance)?
* and so on
* scope pictures, (hand drawn) timing diagrams
* ...

You say you can't turn ON the triac ... but then you say the output us fully ON.
If it's already ON, how will you switch it ON
If it's fully ON, how do you know the triac does not switch ON (since you won't see any difference at the output: ON vs ON)

Unused comparator:
* for unused parts you should give them a "defined state". But shorted inputs ... give no defined output. It will be either high, low, in between or even noisy, oscillating. Shorting the output to GND isn't a good idea at all.
Better set the inverting input a bit higher than the non inverting input...--> defined LOW output state

Klaus

what is the power and load connected to J5 ? if not high enough latching and holding current your Triac may not turn on

what is calculated gate current ?

R11 may be too low