marconi-in: Model variations
The type nuber for my unit should be TF2102M1, as shown on my latest images. .Type TF2102M came later and added a mains switch and power indicator.
Documentation for 2102MI is dated 7-68, for 2102M is dated 5-82
My unit was made in 1976. I no longer require schematics for this model.
Usually, the added letters or numbers behind a "general" type code indicate an updated (later) version or other variants of a device.
The information you provide here only shows that in 1968 there was already a version TF2102M1, either alongside with TF2102M or even the only version of TF2102M that was produced in that time - but not that the model without "1" is newer than the one with a "1".
User manuals sometimes tend to be more generic and do not mention or cover specific versions.
The information should be shown on the model page directly, and I have suggested the according changes.