Keyboards with detachable cables can be very practical. The detachable cable allows the keyboard to be stored and transported more easily, and also makes the process of swapping out the keyboard painless.

The detachable cable is most often connected to the keyboard with a mini-USB or micro-USB connector. Unfortunately, while this system provides the benefits listed above, it also introduces a point of failure. The mini- or micro-USB port on the keyboard wears out and causes the keyboard to stop working properly. Common symptoms of this problem are the keyboard randomly disconnecting, or not being recognized by the PC at all.

In this article I will explain you how to repair a keyboard with a damaged USB port. I have also included a step by step guide on how to do this on a Cooler Master Quick Fire TK mechanical keyboard.

Close-up of the mini-USB connector on the bottom of a Cooler Master Quickfire TK keyboard.
A mini-USB port on the bottom of a mechanical keyboard.

Before showing you how to fix keyboard problems caused by a damaged mini- or micro-USB port, I will first answer some frequently asked questions.

What causes the USB port on the keyboard to break?

The most common cause of the mini-USB or micro-USB port on a keyboard breaking is that it simply wears out. The port is rated for a limited number of connect-disconnect cycles, and eventually it stops carrying the signal from the connector properly.

Even if a connector or port is rated for a certain number of connect-disconnect cycles, the actual number of cycles before problems occur can be a lot lower. The majority of keyboards are mass-produced, and nowadays it is not uncommon for manufacturers to use cheaper, lower quality components in order to save costs. Lower quality components break a lot quicker than their quality counterparts.

Oftentimes this results in a product becoming unusable at some point, because of a couple of cents saved on something like a switch, USB port, etc.

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Luckily, it is not too hard to repair these problems.

How can you tell if the problems are caused by the keyboard’s USB port?

When a keyboard’s USB port starts failing, there are a couple of symptoms that can show up. For example, the keyboard will begin randomly disconnecting and reconnecting to the computer, or it will not be recognized by the computer at all. Sometimes, wiggling the cable connector in the port can solve the problem, but that is usually only temporary.

Before opening up and repairing the keyboard however, it is important to first exclude other possible causes of the problem. Try a different USB cable, different USB ports, and if possible connect the keyboard to a different device to see if it works there. Also make sure to install any required drivers for the keyboard.

If the keyboard has the same problem in all other configurations, then it is definitely the keyboard that is causing the issue.

If nothing else damaged the keyboard (e.g. liquid spilled over the keyboard), then it is likely that the USB port is what is causing the connection problems.

How can you repair the mini- or micro-USB port on a keyboard?

There are two main ways in which the USB port on a keyboard can be fixed. The first one is to replace the USB port on the circuit board of the keyboard. The second one is to remove the USB port altogether and to solder the USB cable directly to the electronics of the keyboard.

Replacing the mini- or micro-USB port

The USB port on the keyboard can be replaced by de-soldering the old port on the keyboard’s circuit board, and soldering in a new one. This is quite tricky to do by hand with a soldering iron, because of the small pins on the port. The best way to do this is to use a hot air rework station instead.

At the time of repairing the Coolermaster Quick Fire keyboard I did not have access to a hot air rework station, so this method is beyond the scope of this article. If I get my hands on a second keyboard with this problem however, I will document the process with a hot air rework station and update this article.

The advantage of replacing the USB port is that the keyboard keeps its detachable cable, but there is a risk of the USB port developing the same issue in the future.

Soldering the USB cable directly to the keyboard’s electronics

The alternative is to bypass the USB port altogether, and to solder the USB cable directly to the electronics of the keyboard. This can either be to a circuit board in the keyboard, or (as in the case of my keyboard) to an internal USB cable. This fix is a lot easier, as it only involves manually soldering four wires.

When repairing the keyboard like this, it does lose the detachable cable functionality. But you will never have to worry about problems with the mini-/micro-USB port again.

I personally rarely detached the cable anyway (and yet the USB port still broke), so not being able to detach it is not an issue for me. It’s still not ideal, but it beats buying a new keyboard.

Further down the page I have added a step-by-step guide on how to solder the USB cable directly to the keyboard’s electronics.

Does this guide also work for keyboards other than the CM Quickfire?

While the guide below shows the repair process on the CoolerMaster QuickFire TK keyboard, it should be possible to use it for other keyboards as well. The steps will be fairly similar on other keyboards.

What is important is to identify where you should solder the wires from the USB cable to.

In the case of the CoolerMaster QuickFire, the keyboard has an internal cable that carries the USB signal. I could simply attach the external USB cable to the internal one.

I suspect many other CoolerMaster keyboards to have a similar configuration.

Other keyboards that are not wired like this might still have pads for the USB signal on the circuit board. These are usually labelled something like VCC, D-, D+ and GND and can be found close to the USB port.

Read on to see the step by step guide for fixing USB port issues on a CoolerMaster QuickFire keyboard.

Materials

Tools

How to repair a CoolerMaster Quick Fire TK keyboard – Step-by-step

Opening the keyboard

The bottom of a Cooler Master Quickfire TK keyboard with the locations of the screws circled.
Remove the seven screws on the bottom of the QuickFire keyboard. Five of the screws are immediately visible. The other two are located under the rubber pads at the top.
A hand using a screwdriver to lift off the rubber foot from the bottom of a keyboard.
To access the two screws under the rubber pads, lift the pads off with something thin like a screwdriver.
Two hands separating the unscrewed top and bottom halves of a Cooler Master Quickfire keyboard.
Detach the top and bottom plastic keyboard sections.
Top view of a Cooler Master QuickFire TK keyboard with the top plastic cover removed and placed above the keyboard.
The keyboard will now look something like this.

Removing the PCBs

A hand holding a screwdriver unscrewing a screw on a partially disassembled computer keyboard.
Remove the four screws on the white circuit board that contains the mechanical key switches. There might be a fifth screw in your CM QuickFire TK, but my keyboard did not come with that screw installed.
Top view of a partially disassembled QuickFire TK computer keyboard.
Unscrew the small PCB that has the mini-USB port on it. It is mounted with either one or two screws. You will need to move the large PCB with keyswitches out of the way first, before you can access the smaller one.
A hand holding a small PCB of a computer keyboard, with in the background the disassembled keyboard.
After removing the screw, the small circuit board can be taken out by hand.

Modifying the detachable USB cable

A hand holding a pair of pliers that is used to cut through a braided USB cable with USB mini-B connector.
Clip the mini-USB end off of the detachable USB cable. Double-check whether you are cutting off the right end of the cable.
A hand using a box knife to remove the braided sleeving of a USB cable.
Use a box knife or small scissors to remove about 25mm / 1″ of the braided sleeving from the USB cable.
A hand holding a USB cable without connector that has a part of its braided sleeving removed.
The cable will look something like this now.
A wire stripper tool being used to remove the insulation from a USB cable without connector.
Use wire strippers to remove about 12mm / 0.5″ of the insulation of the USB cable.
A hand holding up a stripped piece of USB cable, showing the internal wiring.
The exposed wires and shielding.
Close-up of a USB cable with exposed wiring that is sticking out of a hole in an element of a computer keyboard.
Insert the cable through the USB port hole in the keyboard case.
A soldering iron and soldering tin being used to tin the tips of exposed wires of a USB cable.
Strip a small bit of insulation from the four wires, and tin the copper ends. Also twist and tin the small strands of shielding.

Removing the small PCB

A hand using a pair of pliers to clip a ground wire on a small PCB.
Clip the ground wire from the small PCB.
A soldering iron heating up solder connections with wires on a small green PCB.
Desolder the USB wires.

Soldering the USB wiring

A hand sliding a piece of heat shrink tubing over exposed wires of a USB cable. In the background a large PCB of a computer keyboard.
Slide a ~20mm / 0.75″ long piece of large heat shrink tubing over one of the USB cables.
A hand holding a USB cable with exposed wires that have unshrunk heat shrink tubing over them.
Place a ~10mm / 0.4″ piece of heat shrink tubing over each thin wire.
A soldering iron being used to solder two red wires of two USB cables together. A third hand tool is holding one of the wires in place.
Solder each wire of the first USB cable to the corresponding wire of the second cable (red-red, green-green, etc.). You can use a third-hand tool to keep the wires in place while you solder them.
Warning icon
Be careful not to heat the wires for too long, otherwise they can get too hot and the heat shrink tubing will prematurely shrink.
Two USB cables that have each of their red, green, white and black wires connected with solder. On the wires is heat shrink visible.
The wires after soldering.
A hand holding a lighter that is being used to shrink four small pieces of heat shrink tubing on the wires of a USB cable.
Slide the four pieces of heat shrink tubing over the solder joints, and shrink them using a lighter or other heat source.
A hand holding a lighter that is being used to shrink a large piece heat shrink on the wires of a USB cable.
Slide the large piece of heat shrink tubing over the smaller ones and shrink it down.
A hand holding a piece of wire that is simultaneously being soldered to a second piece of wire using a soldering iron.
Solder the ground wire to the shielding of the external USB cable with the same method: first add heat shrink tubing, solder the wire to the shielding and then shrink the tubing over the solder joint.

Finishing up

A USB cable that has been soldered to a different USB cable. The solder joints are insulated with heat shrink tubing.
The soldering part is now complete. This is a good moment to plug the keyboard into the computer to test if the keyboard works as it should.
A hot glue gun squirting glue over a USB cable on the inside of a computer keyboard.
Gently bend the cable 90 degrees and secure it in place with a liberal application of hot glue. Aside from keeping the cable in place, the hot glue also helps insulate some of the exposed shielding of the USB cable. Without it, the shielding can short circuit the solder joints on the bottom of the large PCB.
A Cooler Master Quickfire TK keyboard with the protective plastic top removed.
The white circuit board is placed on the plastic base of the keyboard and the steps for disassembly are done in reverse to reassemble the keyboard.
Info icon
During reassembly, you can apply a tiny amount of hot glue to the underside of the rubber feet if they do not stick by themselves anymore.
A Cooler Master Quickfire TK keyboard with in front of it a tiny screw.
That is all there is to it! I had one small screw left in the end, because the small PCB with the USB port did not need to be placed back.

A summary of the repair process

  1. Unscrew the screws from the bottom of the keyboard.
  2. Remove the top plastic cover.
  3. Unscrew the screws that hold the main PCB in place.
  4. Move the main PCB out of the way and detach the smaller PCB.
  5. Modify the detachable USB cable to get it ready for soldering.
  6. Desolder the USB wiring from the small PCB.
  7. Solder the two sets of USB wiring together.
  8. Heat shrink the solder joints.
  9. Hot glue the USB cable in place.
  10. Test the keyboard.
  11. Reassemble the keyboard.

Conclusion

Ever since soldering the USB cable directly to the keyboard, it has been working perfectly. No more random disconnects or other problems.

If you find this article useful, please share it or leave a comment. I love to hear your feedback and questions!

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