I'm still working on coordinating resources and scheduling for scanning of the 1985 QBC V rev B cover.
In the meantime I have done some work on designing a replacement filler plate for the back of a 1989 QBC II rev C cover to more closely resemble the rear of the rev B..
This is a rendering of the replacement insert. (STEP file attached) It can be 3D printed or milled on a conventional or CNC milling machine.
This insert can then be glued in place in the existing opening and the joints hidden with filler. It will not be a 100% match in that the slots on the rev B unit extend further outward than the opening in the rear of the rev C shell.
Here is a comparison of the rev B unit on the left and the rev C unit with the new insert on the right
I have noticed a QBC II Plus model 4452 unit has just been put up on ebay
This unit is labeled as 1989 rev A.
It appears to be an injection molded shell of similar if not identical design as the 1989 QBC II rev C.
The seller is asking $485.00 with free shipping. I sent the seller a message that the unit is incomplete in that the transport know used to position the sample tube under the microscope was missing. This might make the price negotiable.
I have no intention of buying this QBC II Plus unit, I'm just putting the information out there.