I got a non-working Flextone III 112 donated to me for use with the high school rock band. It's fault is no DSP. It has to be factory reset and then it'll amplify clean. I figured it'd be fine to go straight into the return with pedals but that method didn't work :-( (edit - I've since seen that I need dummy jack in the input!) but it's OKAY if I go into the main input jack as normal with pedals or use as the amp as a monitor.
My question is, is there a way to fix this with replacement parts from other Flextone models. They come up spares or repair from time to time on auction sites. Currently (Dec 2019) I might be able to buy a III 212 cheap that's blowing fuses.