Capacitor identificiation markings

I'm restoring a German set that I have and found what I believe to be an electrolytic cap that needs replacing. From what I can tell, it's 20uf @ 35 / 40 V. However, what I can't tell, is what the positive and negative leads are. They are marked 1 & 2. See attached photo. I'm not familiar with this designation, can anyone help? It is sincerely appreciated.

• 20 uf Electrolytic (133 KB)

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If both ends of the aluminium can have rubber insulators, it's a non polarized electrolytic. In this case, it is negligible how the electrolytic is soldered in place. Seems to be part of a speaker crossover network.

But i'm wondering if the stated capacitance of this specimen has been degraded. I would not replace this Siemens electrolytic if a) capacitance differs no more than -10% to +20% from printed value and b) the ESR (equivalent serie resistance) is low, about 1...5 Ω at 1 kHz. Usually these Siemens electrolytics are known for reliability although often more than 55 years old.

If replacement is still necessary, use also a non polarized elec. for audio applications (these have smooth electrodes for lower losses) or a plastic foil capacitor.

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Bernhard, thank you so much. It is part of the audio network of a Grundig set. The bottom of the cap is seriously burned (something must have been extremely hot), so I think replacement will probably be necessary. I'll go ahead and test it just in case it can be saved.

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Please specify the Grundig set (type/model), because this thread should be moved to it. Thanks.

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It would be a Grundig 7063W/3D. And yes, that is the one. Thank you all for your help.

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