Vintage Synth Repair

Hello listers,

first of all, thank you for the help some of you gave me in looking for 
info about the TMS3615 chip

now I have a new quest: does anyone know where to find a M-147 chip 
and/or its datasheet ?
it was a 24 pin chip made by SGS/ATES, listed as "13-bit latch pedal 
sustain"
it was used in some organs, and I am sure there is one in the Eko K3
20-note pedalboard

any help would again be very welcome

thank you for this great list

greetings
Paolo Vallebona