Hello all.....O.K. I am taking a shot at this one......I have 2 Gould DSO400 and 1 DSO450 oscilloscopes, unfortunatley one of the 400's is not well.....I traced the fault to a 10uF tant s/c, this took out the +ve rail to one of the input pre-amps......The problem is that it also destroyed the pre-amp I.C......Now these are Gould semi-custom I.C,s and of course are obsolete now.....Can enyone help????? The Gould part number is 456617.......Thanks in advance (well you never know !!)....Daniel..