Introduction

If your amp has a faulty input jack, as evidenced by audio cutting in and out, then we need to replace the jack. This is a very common piece to break as cables are constantly plugged and unplugged from this jack. In this guide, we will disassemble the amp, remove the amp head, remove the front PCB, and replace the old jack with a new working one.

Image 1/1: Take off the back panel by unscrewing the four screws on the back of the amplifier. The back panel lies in front of the back of the amplifier head so we must remove it to access the input jack.
  • Make sure to unplug the power cord!

  • Take off the back panel by unscrewing the four screws on the back of the amplifier. The back panel lies in front of the back of the amplifier head so we must remove it to access the input jack.

  • Keep the screws in a safe place and mark what part they are for.

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Image 1/3: Remove the quarter inch speaker cable from the jack in the back of the amp. Image 2/3: Unscrew the three remaining screws on the back side of the amp head as indicated by the red circles. Be sure to keep the amp secure as you do this because it will no longer be supported by any screws Image 3/3: Carefully remove the amplifier head from the speaker cabinet.
  • Remove the four screws on the top of the amp. These screws are significantly longer than the back panel screws.

  • Remove the quarter inch speaker cable from the jack in the back of the amp.

  • Unscrew the three remaining screws on the back side of the amp head as indicated by the red circles. Be sure to keep the amp secure as you do this because it will no longer be supported by any screws

  • Carefully remove the amplifier head from the speaker cabinet.

  • Refer to the guide on replacing the Power Tubes and Preamp Tubes to remove the tubes from the amp head. This is so you can safely set the amp head down without risking breaking a tube.

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Image 1/3: Start by removing all the knobs with a small, flat screwdriver Image 2/3: Use a wrench or pliers to remove all the nuts that were under the knobs Image 3/3: Use the wrench or pliers to also remove the nuts on the normal and vibrato input jacks
  • It's time to remove the front PCB (Printed Circuit Board)

  • Start by removing all the knobs with a small, flat screwdriver

  • Use a wrench or pliers to remove all the nuts that were under the knobs

  • Use the wrench or pliers to also remove the nuts on the normal and vibrato input jacks

  • Use a screwdriver to remove the screws on the bright switches

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Image 1/3: Caution! While working in the amp head, use only one hand to ensure safety from electrical shock. This is a rare occurrence but only using one hand will protect you. Do not "ground" yourself by touching anything else with your other hand. Do not touch any unfamiliar components. Image 2/3: Locate the three pin connecters between the two PCBS. Gently unplug them by pulling straight up. Image 3/3: Remove the PCB from the amp head and set it aside to get ready for soldering
  • Ensure that the front panel is free by pulling back the black cover. If it does not pull back, remove any remaining nuts or screws

  • Caution! While working in the amp head, use only one hand to ensure safety from electrical shock. This is a rare occurrence but only using one hand will protect you. Do not "ground" yourself by touching anything else with your other hand. Do not touch any unfamiliar components.

  • Locate the three pin connecters between the two PCBS. Gently unplug them by pulling straight up.

  • Remove the PCB from the amp head and set it aside to get ready for soldering

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Image 1/3: Once the soldering iron is hot enough, touch the tip to the solder joint on the PCB while using tweezers to clear out a big enough hole to pull out the jack Image 2/3: Remove the jack once the joints are broken and clean out excess solder Image 3/3: Remove the jack once the joints are broken and clean out excess solder
  • Set your soldering iron to a medium to hot setting to adequately melt the solder joints

  • Once the soldering iron is hot enough, touch the tip to the solder joint on the PCB while using tweezers to clear out a big enough hole to pull out the jack

  • Remove the jack once the joints are broken and clean out excess solder

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Image 1/3: Hold the iron tip near the joints with the solder. Image 2/3: Melt a bead of solder onto the iron and drop it right on the joint while adequately spreading it to ensure proper connection Image 3/3: Melt a bead of solder onto the iron and drop it right on the joint while adequately spreading it to ensure proper connection
  • Insert the new jack into the holes that were left behind by the old jack

  • Hold the iron tip near the joints with the solder.

  • Melt a bead of solder onto the iron and drop it right on the joint while adequately spreading it to ensure proper connection

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Image 1/1:
  • Repeat steps 6 through 1 in reverse order to rebuild your amp! Ensure to always use only one hand in the amp and to keep your tubes safe.

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Conclusion

Now your amp is in perfect working condition! Keep on rockin.

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Andrew Krippner

Member since: 01/21/2014

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Cal Poly, Team 9-27, Maness Winter 2014 Member of Cal Poly, Team 9-27, Maness Winter 2014

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