This pedal is a sleeper. It is dirt cheap (~18€ in Finland) but has an SMD-version of PT2399 delay chip which is the same chip I used in my Time Machine and Hyperizer pedals… Originally Fab Echo doesn’t have an adjustable delay time and is fixed to just slapback echo. If you take out a resistor connected to pin 6 of the PT2399 and replace it with a 50-100k pot to ground you have a delay time control! I used a 50k mini pot to make it fit nicely beside the other pots. Just had to drill one hole for it (pics). Be really really careful when working with smd-components because they just fall off if you touch them with a hot soldering iron!
To get infinite repeats and self oscillation (when repeats-knob is at maximum) I put a solder blob to connect a resistor and one leg of a big cap you see in the pics. Originally these caps are on the other side of the pcb but since I installed a delay time pot there was no room anymore. Changing caps to the other side actually made this mod easier :)
Finally I used a jumper cable to get more wet sound volume from the mix-pot (rightmost mod in the pics).
After these mods it’s a nice analog/lo-fi sounding delay with self oscillation capabilities. For under 20€ it’s a steal and sounds Fabtastic! :)
Idea for the mod from Earthtonesaudio @ diystompboxes.com