Fender Amplifier Troubleshooting
Leo Fender began making amplifiers for his electric guitars in 1946. Fender quickly became the dominant amplifier and electric guitar company in the United States, with its amplifier technology setting the standard. Marshall amps became Fender's major competitor in the 1960s as rock guitarists searched for more power to play very loud rock music. The first Marshall amps were modeled on the 1959 Fender Bassman amp. Part of the charm of Fender amps is their simplicity, which makes basic maintenance and tune-ups something that most guitar players can do on their own. If your Fender amplifier gets a lot of wear and tear, take it in for a professional tune-up once a year.
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Things You'll Need
- Phillips screwdriver
- Brush
- Cloth
- Compressed air
- Toothbrush
- Wire cutters
- Wire strippers
- Soldering iron
- Spray contact cleaner
- WD-40
- Wrench
Instructions
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1
Unplug the Fender amplifier and allow it to sit for a few days. This allows the filter caps to lose their charge.
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2
Remove the amp chassis by unscrewing the upper back panel to give you access to the amplifier. Unscrew the chassis from the case.
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3
Clean dirt, dust and debris. Many amplifier problems are caused by dirt and dust. Clean off all the parts of the amp that you can reach with a small brush and cloth. Clean more difficult areas with compressed air and a toothbrush.
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4
Examine all the soldered connections. Loose or damaged connections need to be soldered again. Repair wires that are torn and frayed by clipping the bad parts off with wire clippers. Strip off enough insulation to make a new connection.
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5
Spray the control potentiometers with contact spray cleaner. The pots (as they are more commonly known) on the amplifier can become contaminated with dirt and debris. The result is scratchy and crackling when you try to adjust the knobs on the amp. Spray contact cleaner into the pots and turn the knobs all the way to the left and then all the way to the right. Do this a few times to thoroughly clean the pots.
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Remove the power tubes and preamp tubes. The number of tubes depends upon your model of Fender amp. Clean the tube sockets with contact cleaner. Work on one tube socket at a time. Spray the socket with contact cleaner. Use a small brush or tooth brush to remove the grime. Spray the socket with WD-40 to keep it lubricated. Repeat the process until all the tube sockets are clean.
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7
Tighten the nuts and bolts that hold together the amplifier. Over time the nuts and bolts become loose, causing rattling and other annoying noises and may lead to more serious problems. Tighten the transformer screws. On Fender Tweed amplifiers the screws holding the transformer in place also serve to ground the amp. Inspect all the other nuts and bolts and tighten as necessary with a screwdriver, wrench and pliers. Replace the amp chassis.
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8
Inspect the speakers. Speakers on Fender amplifiers are held in place by four screws The screws become loose over time because of the sound vibrations. Make sure all of the screws are tight. Don't over-tighten the screws as the speakers need to move. Plug the amp in and turn it on. Plug a guitar into the amp and set it at low volume. Play the guitar and listen to each speaker. If the speaker is ripped or torn it will sound distorted. Repair minor rips and tears with glue or tape. If the speaker is blown, it needs to be replaced.
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9
Inspect the tubes. Leave the amplifier on and pay attention to the color of the tubes. The tubes should glow with a medium orange color. A blueish glow means that the tubes are weak. If the color is bright red, this indicates the tubes are too hot. Replace the weak and over powered tubes. All amps are designed for specific types of tubes. Fender amps typically use 6L6 power tubes and 12Ax6 preamp tubes. Read the manual for your Fender amp as it is essential to replace with the correct tubes.
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Tips & Warnings
Avoid touching the filter capacitors; they are cardboard cylinders. On Fender amps they are usually tan or orange in color.
Stay away from the wires leading to the transformer. This is a discharge path for the filter capacitors.
