How to repair an Xbox Remote Control - Decoupling Capacitor Fix

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How to repair an Xbox Remote Control - Decoupling Capacitor Fix

Post by Corp Dwayne Hicks on Mon Mar 21, 2016 9:17 pm

This is written in response to having a broken Xbox Remote Control.

The symptoms are that the remote seems to fire OK. When i point the remote at a  TV receiver just for test purposes, I can see a red LED flashing on the receiver set but when pointing the remote towards the Xbox receiver there is no response to any button presses.

So a while ago i dismantled the remote and connected the Infra-red output to a Oscilloscope. The signal coming
from the scope was a particularly noisy pulse train so i suspected the decoupling was poor on the PCB.

The addition of a small surface mount capacitor close to the power pin where the battery voltage is supplied to the IC
cures the problem. You can salvage the capacitor from an old phone OR USB stick as per my example.

You can see the supplement capacitor in the photo below. It is stood vertically of the Power pin of the IC. The additional green wire is connected to 0V (Ground) on the PCB.

I think the real problem lies with the poor choice of decoupling capacitors. The Xbox remote control has only
an Electrolytic which is prone to leaking and also not positioned close enough to the IC due to the mechanical nature of the assembly being a single sided PCB.

Note, this fix may well work for other remote controls which have poor decoupling OR leaky capacitors.

Step 1: Open the Xbox Remote - Identify IC and Check Electrolytic Quality

You will need a screwdriver and penknife to open the remote control plastic assembly.

There are two places either side of the remote to insert the screwdriver blade. (See photos).

Once you have clicked open the the plastic either side you will need a pen knife to work
along each side of the plastic to release and split apart the plastic assembly.

With the Assembly open its a good time to check the IC number. I hope this is the only IC that the  Xbox
people made but you can check it here. The IC chip number should be the same apart from manufacturing
batch codes and date stamps. Again see photo where IC is under the magnifying glass.

Now is also a good time to check the state of Electrolytic Capacitor (Value - 47uF 25V). Check for gunge/liquid
substance running out the bottom. around the component legs. My capacitor had failed but i actually left it in
and just added the supplementary capacitor. The photo with a screwdriver blade pointing to a capacitor shows you which one it it is.

You could replace the Electrolytic Capacitor but its most likely to fail again. The surface mount capacitor fix we are going to add has no leakage problems.

Step 2: Get Components - Find a Supplementary Capacitor to use and some wire

The capacitor for the Xbox remote i used was a surface mount.

I found mine on an old phone but broken USB sticks are good source as they have a few decoupling capacitors
close to the IC's on the PCB which are easy to identify and remove.

The photos with this step show the capacitors from an old USB stick pointed to by a scalpel blade.

Do not worry to much about the exact value of this capacitor. An ideal value would be around 100nF
but most of the capacitors placed around IC's should be close to that value.

Remember your capacitor is a supplement to the Electrolytic that already exists. The supplement capacitor
positioned close to the leg of IC will improve decoupling.

To get the capacitors off you will need to place the soldering iron across both ends of the capacitor so you
heat both ends simultaneously.

As the solder melts you will end up with the capacitor stuck to the soldering iron tip and you can wipe it off the tip with a screwdriver or knife. With the Capacitor lifted check no solder bridges exist between both ends of the capacitor. You can hold the Capacitor with tweasers and gently re-flow the solder terminals of the capacitor just to tidy them up.

You should now have your supplementary capacitor.

The small green wire  used is nothing special. Just a fine insulated wire will do which could be salvaged from any other broken electrical items.

Step 3: Add the Supplementary Capacitor to the IC

You are now going to add the capacitor to the IC as per photo.

You can see the electrical connections you are making from the simple paper schematic photo.

One end of the capacitor is soldered to pin/leg 6 of the IC and the other end of the capacitor is wired back to the zero volts/ ground of the the PCB.

While holding the capacitor with tweasers, heat pin/leg 6 of the IC with a soldering iron and push one end of the capacitor to the IC leg and then remove iron and allow to cool. The capacitor should be stand vertically of the leg of the IC.

Now heat the other end of the capacitor and tack a small insulated wire to it and connect the other end as per photo. This is the green wire in the photos.

You should now have a capacitor mounted.

If you have a multimeter you could do some continuity checks of the connections.

You could also hot glue the capacitor and wire  to give it some mechanical stability if necessary.

Step 4: Finishing Off - Clean up, Test and Re-Assemble

Before complete re-assembly it is good to clean up the PCB switch contacts on the PCB.

You can wipe these over with a little bit of spirit (methylated or white) on a cotton wool
bud. Be gentle with these contacts as they are only silkscreen on! (See Photo of switch contact)

The rubber keypad and plastic assembly if dirty can be cleaned in warm soapy water with an old toothbrush and
left to dry out Make sure the keypad is completely dry before test and Re-assembly.

Now test out your modification with a partial assembly.

Rest the PCB in the bottom plastic assembly and Re-insert batteries.
Now  temporarily  locate the rubber button keypad over the PCB button side by just resting the top plastic assembly
on top. Press the buttons and check for response on the Xbox.

Hopefully as this point you will have a working remote and you can re-assemble the remote.

If not go back and check your solder connections are correct and of good quality.
Also check batteries if the remote has been lying around for long time.

Note, this fix may well work with other faulty remotes but the you will have to reverse engineer the connectivity of the battery supply to the IC to know where to add the capacitor. Always aim to place the capacitor as close to the IC as possible without interfering with any of the plastic assembly.

So don't bin that remote just yet......have a go !!
Corp Dwayne Hicks

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