In the meantime, I have managed to replace the drawband of the Plana, which was done in 5 minutes. Very easy job on that machine. By the way, its serial is 1607, thus dating it to first year of production, 1939. That made me really happy. Seems that everything works nicely on this machine, have to see though for the quite complex margin-and-tab mechanism. I hope after cleaning and maybe lubing I will get it to working to full extent, even the drawband that links the left button to the actual mechanism at the rear of the machine is in place, so eventually I hope I will be able to describe the way it works in detail, which I guess nobody has done so far?

Or anyone here have an idea which of the two possible positions of each the two keys right and left of the space bar should result in what action? I guess the four options are set margin, set tab, de-set margin or tab, and jump to tab?

The machine is the same like that one here: http://www.swingingtypebars.com/2012/10/a-week-of-reviews-part-eight-olympia.html, with hardly any signs of wear, very light typing action and, sigh, a fully batterd case which I guess was broken open due to the key having gone missing.
Stay tuned

 

Good morning, everybody! I am happy to announce that I have understood the tab and margin mechanism on my 1939 Olympia Plana A Enjoy!

Full review of this mechanism (photos to follow, for the time being see the images in the link I posted earlier in this thread; and many thanks to the guy who wrote that post sme years ago, as his observations helped me to go further and fully resolve the riddle):

There are two buttons right and left ot the space bar, both displaying two icons each. Both buttons may be rotated and will rest in one of two positions corresponding with one of the two icons. Both buttons have a small screw protruding from the stem, which results, depending on the position of the button, in one or two linkage systems being activated. Thus you get  four possible actions: (left button) Set margin, icon is horizontal line with two arrows rising from the two ends, Set tab, icon is one arrow rising from the middle of a horizontal line, and (right button) Jump to tab, icon is vertical arrow, and Clear tab and margin, icon is double horizontal line with arrow rising from the middle.

The mechanics at the back of the machine are the typical Olympia tab sytem: A series of little levers, one for each  increment all along the carriage. What the left-hand button does, is depress those little levers. For a tab, it will only use one link of the mechanism, and depress the respective lever in the back halfways. For a margin, the button, with the help of the little screw protruding, will activate both links to the back, thus enabling the little levers to be depressed further down. This is achieved by a thread, soft white material, the same that is often seen as drawchords. This thread pulls a  lever out of the way, so that the tab levers can go down further. The 5 center tab levers can only be used as tabs, not as margins. They are shaped differently, bigger, and therefore cannot go down all the way in oder to trigger the margin action. Regarding the thread doing the margin job, I guess this is likely to be gone in many cases on these Plana models. Pretty hard to figure out that there should be this type of linkage when it's not there ... Finally, when passing over a margin with the margin release key, that key will also need to be pressed to go back into the set typing area.

Now, the right hand button is evident: The single arrow position will make the carriage jump to the next set tab, (tab break seems to be working very well here, will have to wind the drum better, which for typing has enough tension, but not for the tabs) and the other position unsets margins and tabs, only that it seems to be that it does not work the way we are used to: Jumping to a tab and pushing the unset button doesn't do the job, same for margin. I had to press the button and slide the carriage over tab or margin, which made the backside levers go up in their idle postions.

I am ever so happy that - while the machine is still uncleaned - e-ve-ry-thing works per-fect-ly and that I managed to figure out the mechanics. Not sure wether to consider that mechanism brilliant or ovedone, though. Olympia engineers and their obsession of elaborate mechanisms ... But there's an easy fallback: Even when the buttons and linkage towards the back would't work, you can manipulate both margins and tabs easily with your fingernails.

Oh, while I am at it, there is something else special about this Plana: On the horizontal bar that holds down the paper on the platen, as usual, the increments are marked, one mark for each, and a 0, 10, 20 etc. every ten increments. Overall that scale goes from 0 to 80, with 4 marks beyond that on either side. Now, up until 30, everything is like normal. But starting with 40, and going through to 80, the tenners are double marked on the bar: 4040, 5050, and so on, with the second number being red, the others, from 0 through 80, are black. What is that, any ideas?

Pity on this marvellous Plana is the battered case, and the rock hard platen, but, hey, you can't have everyhing on a beautiful old lady like that ...

Have a nice weekend, everybody.