Pds8000 echo plus schematic?

[dminner]

Does anyone have a schematic for a pds8000?  I have searched and searched and see multiple threads but all have dead links.  I am curious if I can add a small modulation board to it.

[rutabaga bob]

Have you contacted DigiTech?

[Fender3D]

According to other PDS schematics, they share the same VCO: 3 inverters (or 3 NANDs used as inverters).
Locate the delay potentiometer, around there you'll find VCO.

Check PDS2020 schematic for LFO.