Hello Baldnic,
Check to 110 volt mains wiring to the amplifier for any shorts on the cable.
Check the amplifier for any obvious overheating of componants around the rectifying valve (or substituted diode pack).
The volages on the amplifier are going to be 300 plus volts DC so be careful, my avice is to send the amplifier to a Rowe Ami specialist to be tested/repaired.
Regards
Alan
Alan Hood
ami-man
UK