2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/4911We investigate FUSE spectra of three PG1159 stars and do not find any evidence for iron lines. From a comparison with NLTE models we conclude a deficiency of 1-1.5 dex. We speculate that iron was transformed into heavier elements. A soft X-ray Chandra spectrum of the unique H- and He-deficient star H1504+65 is analyzed. We find high neon and magnesium abundances and confirm that H1504+65 is the bare core of either a C-O or a O-Ne-Mg white dwarf.To be published in: Proceedings 13th European Workshop on White Dwarfs, NATO Science Series, 4 pages, 1 figureAstrophysicstext