Replace diodes CR6 through CR9 and test C31 and C33 for short. If all OK and fuse still blows, remove the power tubes and test. Hopefully you do not have a transformer short.
To save fuses, put a 150 watt light bulb in series to act as a reseting fuse while testing.
This is more commonly caused by one of the output vales 6L6's being faulty. If the fuse stay's intact when switched on with the valves removed this will prove the point. You will need professional help with valve replacement and bias adjustment. Another thing to consider is a possible short circuit smoothing cap.
Answers & Comments
Replace diodes CR6 through CR9 and test C31 and C33 for short. If all OK and fuse still blows, remove the power tubes and test. Hopefully you do not have a transformer short.
To save fuses, put a 150 watt light bulb in series to act as a reseting fuse while testing.
This is more commonly caused by one of the output vales 6L6's being faulty. If the fuse stay's intact when switched on with the valves removed this will prove the point. You will need professional help with valve replacement and bias adjustment. Another thing to consider is a possible short circuit smoothing cap.