Michealson & Austin TVP-X preamp 250 mA fuse on the power unit blowing

Hi I am first time here and need help with the Michealson & Austin TVP-X preamp and it blew a fuse so I checked and found two transistor and a zenor diode burnt out and replaced it but is still blowing the fuse please help with the issue what could do next to fix the problem it worked fine since 1988when I moved to Canada