Let's play a game.
[IMGDEAD]http://www.themusiczoo.com/images/Fender_Amplifiers/Fender_Twin_Amp_0215700000_500.jpg[/IMGDEAD]
I was practicing tonight for a gig tomorrow at a local festival. About an hour into the practice (not running very hard and not playing constantly), my Fender Pro Tube Twin Amp stopped working. I don't have time (or really the knowledge) to troubleshoot and fix it myself, so I'm taking it in tomorrow morning in hopes that my local tech can get it working. Let me tell you about it and tell you what I've checked so far. Let's see who can guess the problem.
Seriously, the real problem is that I will have to use a solid state MG series Marshall instead of my tube amp. I will try to make it out alive.
For a while now, the amp has had an intermittent hum that isn't loud, but annoying at times. The hum volume was consistent regardless of the position of any volume/gain/tone/reverb/etc knob on the amp. Nothing made the volume of the hum change. The hum would show up when the amp was cold or hot. It would go a way whenever it felt like it.
When the amp stopped working, the hum was there, but no signal from my guitar could be heard. After a little troubleshooting, the hum is no longer there. I can not detect any sound at all coming from the speakers at this point.
I pulled the three fuses (main fuse and two under the balance & bias plate) and checked for continuity, but all three were good. I swapped every tube in the amp with old tubes I have that were still working just fine when I swapped in the TAD power tubes and JAN Phillips preamp tubes I now have.
I pulled the chassis out of the enclosure and visually inspected things... lots of capacitors and resistors in there. There was no obvious damage. I screwed everything back together.
The power tubes are about 4 years old and the preamp tubes are about 2 years old. I play somewhere between 6 and 8 hours a week. I drive the amp hard enough to sometimes need the full power setting, but I might be able to get away with the 1/4 power setting most of the time if I tried. I definitely don't run hot enough to overdrive the clean channel. I use both clean and gain channels. I use the vibrato occasionally. I never use the reverb. I use a few pedals from time to time to either get a different distortion sound or boost the level for lead work. Those are in line on the input. I have a multi-effects pedal I run through the effects loop, but rarely use it for anything other than a tuner.
That's about all I can tell you that might matter. So get your guesses in and see if you can call the busted part(s).
Here's a schematic of the amp if anyone wants to see it.
http://www.schematicx.com/view-schematic/fender-twin-amp-pro-tube-guitar-amplifier-schematic/
[IMGDEAD]http://www.themusiczoo.com/images/Fender_Amplifiers/Fender_Twin_Amp_0215700000_500.jpg[/IMGDEAD]
I was practicing tonight for a gig tomorrow at a local festival. About an hour into the practice (not running very hard and not playing constantly), my Fender Pro Tube Twin Amp stopped working. I don't have time (or really the knowledge) to troubleshoot and fix it myself, so I'm taking it in tomorrow morning in hopes that my local tech can get it working. Let me tell you about it and tell you what I've checked so far. Let's see who can guess the problem.
Seriously, the real problem is that I will have to use a solid state MG series Marshall instead of my tube amp. I will try to make it out alive.
For a while now, the amp has had an intermittent hum that isn't loud, but annoying at times. The hum volume was consistent regardless of the position of any volume/gain/tone/reverb/etc knob on the amp. Nothing made the volume of the hum change. The hum would show up when the amp was cold or hot. It would go a way whenever it felt like it.
When the amp stopped working, the hum was there, but no signal from my guitar could be heard. After a little troubleshooting, the hum is no longer there. I can not detect any sound at all coming from the speakers at this point.
I pulled the three fuses (main fuse and two under the balance & bias plate) and checked for continuity, but all three were good. I swapped every tube in the amp with old tubes I have that were still working just fine when I swapped in the TAD power tubes and JAN Phillips preamp tubes I now have.
I pulled the chassis out of the enclosure and visually inspected things... lots of capacitors and resistors in there. There was no obvious damage. I screwed everything back together.
The power tubes are about 4 years old and the preamp tubes are about 2 years old. I play somewhere between 6 and 8 hours a week. I drive the amp hard enough to sometimes need the full power setting, but I might be able to get away with the 1/4 power setting most of the time if I tried. I definitely don't run hot enough to overdrive the clean channel. I use both clean and gain channels. I use the vibrato occasionally. I never use the reverb. I use a few pedals from time to time to either get a different distortion sound or boost the level for lead work. Those are in line on the input. I have a multi-effects pedal I run through the effects loop, but rarely use it for anything other than a tuner.
That's about all I can tell you that might matter. So get your guesses in and see if you can call the busted part(s).
Here's a schematic of the amp if anyone wants to see it.
http://www.schematicx.com/view-schematic/fender-twin-amp-pro-tube-guitar-amplifier-schematic/
