My adaptor for a router that should give 12 V 1 A stopped working and gave too low voltage about 11.
However a capacitor 10 µF 50 V looked a bit strange, so I removed it and with my ESR-meter I found that it did not work.
Substituted it with a new capacitor and then the charger gave 12 V and was fully functional. I bought 630 capacitors (Bojack 24) from Amazon rather cheap. 0,4 SKr each.