Al just put the TI Silent 700 Model 763/765 maintenance manual up on Bitsavers. (Thanks Al!)
The 763 and 765 are the models using internal bubble memory for between 10,000 and 80,000 characters of local storage. They use either one or two "discrete memory boards", with one 92 Kbit bubble device each, or one to four "dual memory boards", each with two 92 Kbit devices. Bubble memory devices typically have many minor loops, not all of which are usable. TI printed mask data on the label of the bubble device, identifying the defective loops. When a bubble memory board is installed or replaced in the terminal, it is necessary to put the terminal into command mode and issue a test command to enter the mask. The scary part is this warning in section 5.2.4.2: CAUTION Care should be exercised in the installation of the bubble memory mask. If an incorrect mask is entered, the bubble device will not work correctly even if the correct mask is entered at a later time. If an incorrect mask is entered, replacement memory board must be installed because the bubble device is no longer reliable. Intel provided the necessary technical information and hardware to recover corrupted bubble devices in the field. As far as I can tell, TI did not.