nordmende: What is specific for the S version ?

I have a Transita Automatic S 49m S33 with the teak housing.

Does anyone know what the difference is between the Transita Automatic and the Transita Automatic S ?
Visibly, there is an indication located at the left of the volume knob, which can be pulled upwards slightly. The indication is showing two small squares: a full white one and a diagonally divided white/black one.

Technically, I noticed some differences on the audio PCB: different values for some resistors, and a different current runaway protection circuit around trimmer R173 (featuring a thermistor and a diode).

In addition, the driver transistors Tr7 and Tr8 for the audio end transistors are no AC162 types, as indicated on the schematic, but AC151. They look original.

Can anyone tell me where the 'S' is standing for ?

To thank the Author because you find the post helpful or well done.

I discovered that the secondary of the output transformer V2 of this version has a center tab, which is wired to an additional switch V6, part of the volume knob assembly.

So, by slightly pulling up, or pushing down again the volume knob, it is possible to select respectively only half or the full secondary of the output transformer V2.

To thank the Author because you find the post helpful or well done.