During assembly or development of a bubble memory system, it is safer and more convenient to use a dummy load rather than the actual 7110 bubble device. In their BPK72 bubble demonstration kit, Intel include both a 7110-1 dummy load and a seed module.
The dummy load has a couple of resistor packs and half a dozen discrete resistors and the same form factor as the 7110-1 bubble module. The dummy module allows the drivers to be checked for the XY rotating field as well as the pulses for replicate, swap, generate, etc. Of course the 7220 and formatter will not recognize the dummy, there is a great deal of testing that can be accomplished with this module in place. While the original dummy had the same footprint as the 7110-1, the dummy module that I have created is universal for either the 7110-1 or the 7110A bubbles.
The second key element of the bubble support is the seed module. If a bubble loses it seed for any reason, the 7230 current pulse generator is removed from its socket and inserted into the seed module. the seed module is then plugged into the 7230 socket on the bubble board. A quick software routine or a dozen discrete steps recreates the seed bubble to restore operation of the bubble module. Once completed everything is restored to their original location and the user can then recreate the boot loop from the bubble on the 7110.
These to support boards have been created as a single snap-in-two bare board. Full documentation on using these boards can be found in the BPK72 user manual which has been uploaded to this site to the bubble documentation page.
