Right, in terms of hard sync, this is how it should work, except it doesn't... Wired everything up as per pdf below, yet engaging switch only causes vco1 to go silent. Maybe I tapped the wrong pins? If anybody's good at schematics, do have a go!

Q3, Q21 and Q34 here

http://www.fantasyjackpalance.com/fj...chem-below.gif

should translate as T7, T37, T57 in the Behringer schematics (linked above). Checked for pinout on sot 23 versions but nada sync so far. Input welcome.