Long shot I know but just in case, I have a Universum Supersound 16000 which I really like. Works reasonably well (a couple of weird anomalies such as low volume on radio in stereo, fine set to mono) but the tape section is screwed.
I can see someone has attempted repairs before and it is not pretty. If anyone has or comes across a trash box I could purchase or a tape mech from a scavenged box I would be grateful.