Ibanez UE400 Repair

[sws2h]

I recently grabbed one of these and the seller told me the chorus/flanger section sometime acted up, for me it doesn't work at all. On the foot switch the red LED turns on, but doesn't on the unit itself and signal is cut dead. All the other functions work (although the phaser sounds very weak)

Any suggestions on where to start? I'm handy with a soldering iron and have built a lot of kits but when it comes to trouble shooting something new I'm not the best

[Fender3D]

Any suggestions on where to start?...

I think schematic is a good starting point...