Elektor Formant Modular

OH GOD GUYS...!
After a long while carefully removing modules one by one from an old 
Formant that was dusty and dodgy.. but worked... I fitted new front 
panels to 3 VCO's and the 24db filter, removed the PSU to a new box, 
added power plugs to send power to the modules. I finally fitted into 
my rack (that contains some Blacet and Paia stuff) and its stopped 
working!!!
Now its getting power (the VCO LED's on the PW lights up) but theres 
no sound from either the outputs of the VCO's OR the output of the 
filter (which has the VCO's hard wired into it).
I HAVENT connected the little "interface" board, as Im not intending 
on using a keyboard, and theres no 12db filter in the chain, should 
this matter?

Can anyone help?
What could I have done wrong?
Where should I look for errors?
Does the fomant only work if its ALL there? Can the modules work 
seperately?
Does the "interface" board do something that I dont know about? (I 
thought it was only for connecting the keyboard?

Any Ideas/help welcomed

Cheers Mark

PS: In trying to resurect my old modular I seemed to have killed 
it!! :-(((