Hiya
I probably built that A1200 in a 19inch rack module

The 19nch "1U" rack modules were custom built for a company called "Movielink" which was based in River St Richmond, Melbourne. They used hundreds >yes I mean hundreds!< of A1200 in these rack units. When I was there they had over six hundred A1200's in use.
Movelink provides in-house-movies for hotels and motels throughout Australia and New Zealand and used up to 6x A1200's installed into cabinets along with modulators, vcr's and head end master modem etc to provide on demand and scheduled movies.
I was employed as their graphic artist/amiga technician during 1996-2000 and the A1200's were used to provide information and navigation pages for the movie system. Most of these pages were short animations all running off 880k floppies.
The A1200 motherboards were all PAL systems usually bought from Analogic in England after local aussie sources like Megatron were depleted.
So the floppy drive you have in the 19inch rack module is just a standard IBM 1.44 floppy with a custom cable I designed to connect to the Amiga. I does NOT provide diskchange signal.. sorry! But since these machines were only rarely rebooted, ran 24/7 for many years with the floppy contents usually copied into the Ram: device having diskchange wasn't a priority

The A1200 motherboard should have a heat sink on the Lisa custom chip.. heat problems were experienced in the cabinets and the Amiga's suffered from poor ventilation. Random resets and graphic corruption was common until we began to use the heat sink fixed onto Lisa.
Hope that helps
Az