There is no sound being played when cheats are activated (tho that is a great suggestion). It could be tricky to activate it sometimes, I often need to give it a few tries, but it should work to hold c h e a and press t. I would speculate that maybe the keyboard you're using cannot handle that many inputs at once, but I am using the cheapest keyboard I could find, and it works for me.
Maybe I should add an easier way to activate cheats in the next update, something like pressing them in quick succession instead of at once.