blaupunkt: Polarity of choice

Hej

I have this Blaupunkt Frankfurt 7 630 640 000, C 3699841(1970), It says on the cover one can swap the polarity depending on what car one have. Where is this done in the radio?  I just can't find it.

On the top cover one can see VOLT(inprinted) but the pcb board sticking out at the back has minus on one side & plus on the other. I think it should say 6V resp 12V.

Any idees?

BR//Ulf , Stockholm

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Is that not a tab that pulls out?
The orientation sets -/+, if indeed the model is switchable at all.

I think only older models have the 6/12V (my grandfather still had a 6V Volkswagon Beetle in the early 1960s). It's a 1970 / 1971 model and by 1972 even reversible polarity was rare. It wasn't hard to reverse the polarity of some Fords with + earth to negative, that used a dynamo, by "flashing" the dynamo field windings.

The Frankfurt model name was used on different models from 1966 onward. Maybe 1969 was last 6V/12V model.

Most later 1970s Blaupunkt and probably all later years are - ground, +12V only, but if is changeable +/- the tab should pull out. On some models a - uppermost means negative earth/chassis and +12V supply.

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Thank you Michael

Yes, the tab that pulls out. It says - on one side & + on the other. On the lid its indicated Volt though. The text label on the lid indicates one can set polarity & voltage.

I have another radio where the tab says 6V resp 12 Volt, indicated on the lid is Volt. 

However, now, I suspect the lid on the Frankfurt radio, could come from another radio.

Thanks

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Now its up & running//Ulf

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