Welcome @MAT38, to the community!
I also assume that both visible diodes with the markings DUI and DUJ are TVS in SMA package. However, both are probably custom parts as my database, which goes back to the last millennium, has no entry for them. The closest markings are DUC (SMAJ6.5A-TR), DUH (SMAJ8.5A-TR) and DUK (SMAJ12A-TR), so I suspect they are unipolar TVS with a voltage of 9...12V - but the voltage may be completely different.
I'm sorry not to be able to give a more pleasant answer.
Good luck!
/Peter
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