DL-4 Do I need new eprom? powers on passes dry when bypassed- no effect in DL4 MkII / DL4 / MM4 / DM4 / FM4 / AM4 / ToneCore Posted July 26, 2018 i've got a dl4 thats not working- it powers on, passes dry tone through both ins and outs, but does not pass any sound when effect is engaged- all footswitches and knobs appear to be functioning. I just dont get any signal passing when I engage any of the effects. Ive opened it up cleaned everything out with electronics cleaner- I dont see any bad solder joints or corrosion anywhere. Is this the sign that I have a bad EPROM? I tried taking out and reseating the one thats in there but that didnt do anything. Or is the sign of another chip not working properly? Again, the board looks fine. I dont know a ton about electronics but I can check components and voltages and replace components and stuff like that. Any help would be much appreciated! Thanks!