Taking a step back after a year may be a good idea.
Blowing fuses means a short. Most probable reasons for a short is shorted outputs.
This unit has 2 transformers 2 sets of power supplies and 2 sets of primary filters.
While the issue could be bad rectifiers, this is usually not the case.
With power off and the unit unplugged, reinstall good fuses, and measure each large filter cap with a multimeter on ohms scale. They should read as a transistor junction in one direction and open when you reverse the leads. Hopefully the short is only on one side. If you find one or 2 of the filters reading low ohms in both directions when measuring, then the channel they are supporting has the problem. If you don't find any indivdual cap reading bad, measure the plus and minus leads across the 2 capacitors (The + and - leads not connecting to chassis ground). I suggest this because if both transistors in a channel are shorted, it is possible that individual caps will read ok, but the short will show when going across bot (+55v and -55v short)
If you identify a problem there, then go to the channel being fed by the bad readings and remove the outputs, marking the positions of where each went. Check and see if the short is gone. If it is gone, remove the driver board for that channel if possible, and then try doing a dim bulb test. If the short is still there, then remove the 2 rectifier sets for that bad channel. Measure the rectifiers in ohms, as well as the caps. If the short still exists measuring across a cap, you may have a smaller disk cap shorted on the board, or highly unlikely a shorted filter cap.
If the 2 fuses that are blowing are F01 and F03, then the problem can be assumed on the left channel. If its F02 and F04, the issue is on the right channel. If the fuses that blow are an odd and even, then the issue is in both channels. Make sure as well that in the process of troubleshooting you didn't accidently remove an output transistor and forgot to install insulator, or damaged it. An easy way to tell is to use you multimeter and touch the collector (case) with one lead and the chassis ground with the other. If any show dead short, pull the transistor and examine the insulator
Blowing fuses means a short. Most probable reasons for a short is shorted outputs.
This unit has 2 transformers 2 sets of power supplies and 2 sets of primary filters.
While the issue could be bad rectifiers, this is usually not the case.
With power off and the unit unplugged, reinstall good fuses, and measure each large filter cap with a multimeter on ohms scale. They should read as a transistor junction in one direction and open when you reverse the leads. Hopefully the short is only on one side. If you find one or 2 of the filters reading low ohms in both directions when measuring, then the channel they are supporting has the problem. If you don't find any indivdual cap reading bad, measure the plus and minus leads across the 2 capacitors (The + and - leads not connecting to chassis ground). I suggest this because if both transistors in a channel are shorted, it is possible that individual caps will read ok, but the short will show when going across bot (+55v and -55v short)
If you identify a problem there, then go to the channel being fed by the bad readings and remove the outputs, marking the positions of where each went. Check and see if the short is gone. If it is gone, remove the driver board for that channel if possible, and then try doing a dim bulb test. If the short is still there, then remove the 2 rectifier sets for that bad channel. Measure the rectifiers in ohms, as well as the caps. If the short still exists measuring across a cap, you may have a smaller disk cap shorted on the board, or highly unlikely a shorted filter cap.
If the 2 fuses that are blowing are F01 and F03, then the problem can be assumed on the left channel. If its F02 and F04, the issue is on the right channel. If the fuses that blow are an odd and even, then the issue is in both channels. Make sure as well that in the process of troubleshooting you didn't accidently remove an output transistor and forgot to install insulator, or damaged it. An easy way to tell is to use you multimeter and touch the collector (case) with one lead and the chassis ground with the other. If any show dead short, pull the transistor and examine the insulator
