ETI 480 schematic - a thing from the 70-80s

Hi all,
i've just been searching for a schematic for an old ETI 480 Amp.

I was given a box of 'stuff' in the box was a whole heap of electoric bits and i think everything to build one of these amps (if not there is an electorics place a few blocks away) - incuding the power suply (i have a board labeled ETI 480 PS and a big transformer that has a note saying - transformer ........ desiged to be used with the ETI 480 amp)

The only words that is on the PCBs are ETI 480 and ETI 480 PS and on the back of both of them they say 'MAS' if this is any help.

If anyone could help it would be great.

--
BoB

P.S Sorry if i've missed this on someone elses post.