Good machine. Sometimes old is better. Nothing available from the makers. Try Mauritron.com, who are excellent, and have the full service manual. There has also been discussion including the circuit diagram posted on the UK Vintage Repair and Discussion Forum over the past few months. Try that as well, I suggest. Bill m0wpnHi
I have an old Advance instruments OS1000A oscilloscope.
I wonder if anybody knows if and where its manual/schematic can be found.