Some time in January I bought a DD-3 and it's been great. However, the last time I turned it on the LED lit up but I had no delays sound coming from the amp. Guitar yes, just no delay. I tried random settings to see if I could jog it back to health but nothing.

Now I bought this secondhand, so there's no waranty I can fall back on, and I'm just wondering if I could do something to fix this problem. I don't have any electrical knowledge, so a schematic wouldn't really help me out.
Leave it alone for a bit. Try batteries as opposed to a power adapter or vice versa. Try a different signal chain combination if you can.

I've had the occasional glitch with my newer DD7. It almost always tends to be weird stuff like that that fixes it.
100w Peavey Valveking Head
Mesa Rectifier 4x12 Standard Cab
Ibanez RG 321
Boss DD-7
iSP Decimator x2
BBE Boosta Grande
Modded Crybaby
MXR Blue Box
Numark Power Conditioner
Korg DTR-1000
It's on my board, and I always have the input cable plugged in, preventing any possible confusion. The first time it did this was last week, and I returned to it yesterday - I imagine that's time enough. I will say it's generally powered by the board, so I may try batteries, but it isn't looking so good...thanks for the replies, guys.