Junghans Solar 1 solar dress watch mid 90s, runs bad

Emblematic Junghans Solar 1 dress wristwatch. I originally bought it here because I just love the look of those very flat cases and I love solar watches!

Sadly, after changing the capacitor with the right model and letting it charge in the sun for 2 weeks, the watches runs slowly (1h late/day) or not at all sometimes if away from the sun. I don't know if I was sent an old capacitor (Swiss seller) and don't have the patience to try further. It could be this or the coils.

Usual wear marks, wrist strap is chinese milanese style that I fitted, I find it suits the look really well. Saphirre looks in really good condition.