Hi, saw you video on TY on this... so thought you might like a little more information, this is just off the top of my head and have not seen these since 1990 or there about.
For my sins I was a Typewriter Engineer through a lot of the 80's, and used to fix these as well as all the other ETV ranges, The 300 I think was CPM, there was an even older version with WP type capabilities an ET351, that was a beast, with optical encoder equipped motors in the print carriage and dual 5.25" drives, and a fluorescent matrix display, I could hardly lift it, not let alone carry it to my van for "workshop" treatment, it was a seriously fast printer, that only the fastest typists might stand a chance of out-typing.
The reason I mention "Optical Encoder" motors, they were a different technology from the simpler cheaper and newer "Stepper motor" that I think the 2700 has, where both calculated the shortest path for the daisy wheel to spin from any one given position to the next, you could usually get them to buffer by picking letters at 180 degrees from each other. A bigger motor would go faster and as accurately as the smaller ones with the encoders. This had the biggest ones I used to work with, don't know if any are still in working condition.
Some of these also had a finer print density control, i.e. how hard the solenoid (hammer) hit the back, can't remember if this was just an engineer thing or a user setting, but you would not hit the "." or "o" as hard as the "W" or "M" or you would have holes punched through the paper, not to mention the shredded daisy wheels when the solenoid got stuck out due to "something", sugary coffee, correcting fluid, etc. getting in there to set overnight.
Your problem the lack of auto loading of paper, that you may have now solved, is that the "bail bar" lever (the wee rollers) had a switch on it when you either pushed or pulled it further than the movement required to fully move the bail bar out of the way, it engaged the switch, think I may have "repaired" this a few times in my distant memory. Seem to recall fitting a few of the optional interfaces, suspect they were comms boards, either to and or from the 2700 to go to/from other computer systems, cant remember if they were just serial or had parralel etc on them.
You are right about the inverse typing, it used the correction tape to lift off the letter to be printed, this was rubbish on thin paper where it got a bit distorted, but on good quality stuff it did a nice job, the daisy wheels were a bit more advanced with the mirrors for optics to read what type it is, what pitch (10-12-PS) to use, especially important for the PS (proportional spacing) it took 1 space for the "." and 5 for the "W" etc, this would also look rubbish if got wrong. Most of these ETV's could do Mail merges with STD documents and lists of "Clients" names and addresses to insert from another file, cannot remember how clever some of the functions were some were a bit beyond my recall, suspect some of the simple "Typewriter" function were built into EPROMS on the motherboards.
ETV-260 was a bit of a beast too, it was infract a XT pc so therefore the generation before the 2700, which was built as a cheaper device, Olivetti's were regarded as only 2nd to IBM in the office equipment marked and may typing pools, offices banks had dozens of these in them, but being "computerised" and fancy looking, usually the boss, the bosses typist or a place of high public profile had these. I went to Olivetti's HQ in England for a course in these when they were new.
As it was a PC I remember if it was near the end of the day and the user had been kind to me (cup of tea biscuits etc) I would occasionally run INVADERS.EXE from one of my disks and let them play it until they had to turn it off for the evening, can't remember what the resolution was it might have switched into CGA graphics for this game, it certainly was not TXT only, also usually left the users jaw on the keyboard for a while too, while I explained this was a computer a heart and not just a fancy Typewriter.
Recently found some old 720k disk, that probably been long since over written labelled "DIAG260" and "DIAG2700" so there are proper diagnostic programmes for these, think they exercised both the motherboards, keyboards screen printer and comms, if you could find a good one it might be another interesting video, as I enjoyed this one it took me down a long time tunnel.
Thanks.
Mr MTBLeague (also have a YT channel under the same name).