I have the the purple Dano Slapback any mods to make it a more usable delay?

[Wild Zebra]

  One of these guys here http://www.axetopia.com/items/Danelectro/DANDJ3.htm I forgot all about it until today.  I'll have to dig it out.  Seems to me there has to be a resistor limiting the amount of delay time and another for a set feedback. 

[Rob Strand]

I think there's a mod for the FAB Echo in the archive.  While the metal box units generally the same circuit as the plastic box ones I suspect with this unit they will be real close. You should be able to follow the same idea.  If the delay chip is different you might have to do more work.