Purchased a UNISEF TU-502 (70's brand, not "UNICEF") tape recorder. The unit arrived with multiple electrical and mechanical faults, including loose belts, cold solder joints, and an inability to play tapes.

Cleaned mechanical components and replaced all belts. Resoldered all accessible components including resistors, capacitors, and film capacitors. Reflowed cold joints and solder paths. Tested remaining components for functionality with specification sheets.

The unit was restored and is now fully operational. The player no longer damages cassette tapes. Its playing and recording functions were restored, and its time tracker now works as well.