Hello and asking for help with HP 67 power unit

[Tapti]

Dear all,
there are good news and I would like to share them with you just by interest. I canged three of the five capacitors of the logic board, being the two responsible for producing Vgg, and the main capacitor in the output of Vss. Now I have -12,18V on Vgg ! At least one of the two 2.2uF tantalums has had a problem, most probably its ESR value. I measured the caps for capacity and internal short and both were ok.
Just a question belonging to the tanatlum caps on the logic board: There is one cap, 47uF, running from terminal 2 of the inductance to ground. On the board it looks like a tantalum just as the others. But I think at this point a bipolar cap is needed as there is AC coming from the coil. Are there bipolar tantalum caps at all ? I bought a unipolar replacement for this, but didn't touch it in the end. I'm just not sure, whether and how to use an unipolar tantalum at this point.