Trouble shooting a delay pedal

[swollenpickles]

I've put together a delay pedal from a pcb i bought (echonaut from effects layout). When testing it, with the effect engaged i get my straight signal going thorough with just the faintest hint of an effect in the background. It's using 2 x PT2399 chips and wondering if what I'm hearing is the typical response you get with a bad chip? Wondering what's the best way to trouble shoot something when there's still a signal passing all the way through? (I think I worded this badly!)

[Zerro]

If delay is here, though weak level, so chip is working. Mess will be probably in switching part or level pots.