guitarjb44
New Member
- Joined
- Nov 4, 2012
- Messages
- 27
Hello all.
I need to replace two of the four internal fuses in my PRS 25th Anniversary 50-watt amp. I opened it up yesterday and the two fuses that have red wires connected to them (the two on the right side in the photo below) tested open (no continuity).
The problem is: I have not found ANYWHERE, online or otherwise, that stocks ceramic fuses rated at 440v. The tag inside the amp states to use only type 3AG 500mA 440v fuses. Is this a rare or obscure fuse, or am I simply not looking in the right places?
Also: does anyone have a schematic for this amp, or do you know what each pair of fuses is connected to and are intended to protect? I assume the two in question are between the output tubes and output transformer? This assumption is based on the fact that all the tubes and indicator light were working, but I got no sound at all out of the amp. That is the problem I was having that caused me to check the fuses in the first place. I already tried swapping in a known-good preamp tube one at a time. I didn't do the same with the power tubes because they LOOK fine, and these two fuses are clearly blown anyway. Therefore, even if I replaced both power tubes, the amp would still not operate with the fuses blown.
The last time I played the amp was about six days ago. When I turned it on it was intermittent at first- which I assumed was a loose or failing preamp tube- but after a few minutes the intermittence went away. Yesterday, I turn it on, wait a minute, then turn on standby- complete silence. No burning smell or anything else to indicate trouble. And again, all pre and power tubes seem to be operating normally...???
Advice...?
Joe
I need to replace two of the four internal fuses in my PRS 25th Anniversary 50-watt amp. I opened it up yesterday and the two fuses that have red wires connected to them (the two on the right side in the photo below) tested open (no continuity).
The problem is: I have not found ANYWHERE, online or otherwise, that stocks ceramic fuses rated at 440v. The tag inside the amp states to use only type 3AG 500mA 440v fuses. Is this a rare or obscure fuse, or am I simply not looking in the right places?
Also: does anyone have a schematic for this amp, or do you know what each pair of fuses is connected to and are intended to protect? I assume the two in question are between the output tubes and output transformer? This assumption is based on the fact that all the tubes and indicator light were working, but I got no sound at all out of the amp. That is the problem I was having that caused me to check the fuses in the first place. I already tried swapping in a known-good preamp tube one at a time. I didn't do the same with the power tubes because they LOOK fine, and these two fuses are clearly blown anyway. Therefore, even if I replaced both power tubes, the amp would still not operate with the fuses blown.
The last time I played the amp was about six days ago. When I turned it on it was intermittent at first- which I assumed was a loose or failing preamp tube- but after a few minutes the intermittence went away. Yesterday, I turn it on, wait a minute, then turn on standby- complete silence. No burning smell or anything else to indicate trouble. And again, all pre and power tubes seem to be operating normally...???
Advice...?
Joe
