Repair.IT – Sony RM-GD001 Remote Control for Sony Bravia KDL46X2000 LCD Digital Colour TV

Here is another job that was sitting there for some time, having put up with the inconvenience patiently until it was time to look at it.  This remote control for a Sony colour TV had been playing up – first it was unable to turn on the TV – but that was ok, since we use the side power button anyway.  Then we couldn’t adjust the volume, again the side buttons still worked.  How tolerant we are?

Then the input source selector stopped working, so we had to use the side buttons again, to access the menu so that we could choose a different HDMI input when we wanted to play Blu-ray movies.  We went through the same hassle to switch back to the Google Chromecast, etc, until it happened that it was time to do something about.  Maybe the wife complaining also helped to bump up the priority.

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This remote control RM-GD001 was relatively easy to open up.  By opening the battery compartment, I could see two screws that needed removing – this is usually a sign that the job will not be difficult.  The ones where there are no visible means of fastening are usually the harder ones.

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I needed the smallest precision Philips screwdriver since the screw slots were so small and thin.  After removing the screws and the battery, I turned my attention to the bottom where there were two visible holes.  By inserting an angled pair of tweezers into the two holes and pulling upwards, the bottom started to come apart.

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Then once the opening was sufficient, I then use an old plastic card to slide into the opening then around the corner and with a click, the housing started to unlatch.  You could use an old credit card, or used gift card (flybuys etc), since they are all a similar size and great for this purpose.

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Once the two pieces of the housing were separated

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This it was a matter of cleaning the contacts.  I used an alcohol wipe that I had previously bought from Officeworks.  Similar products are available from chemists, pharmacies, computer stores etc.  You have seen them before – nurses use them to clean the skin before giving you a needle.  The good thing is that when it dries there is no residue, unlike methylated spirits.

If you are quick, you can use the same wipe to clean both the black circuit board contacts and wipe down the black rubber buttons which press down onto the circuit board.  Once these were clean, I was able to put the batteries in, lay the rubber button overlay onto the board and try pressing some buttons and confirm that they do work.

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Now was also a good time to clean the top surface of the remote control as the buttons are not going to get in the way.

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Now that this is relatively clean, I clipped the two housings back together, put the screws back in, and I have a functional remote control again.  Another successful repair.

[Note 1]  It can happen that with use, the conductive coating on the buttons are worn out.  We can get a conductive paint and just paint onto the buttons again.  This is available as a remote control repair kit, that I have seen on eBay but not used.  Others have reported gluing thin pieces of aluminium foil onto the buttons.

[Note 2]  What if you want to test the buttons, but the appliance is not available?  I will explain how to do this with a common webcam attached to a computer.  I have this webcam that I put onto the table, and aimed it where I was working.  With the display on the monitor, I could press a button and confirm that the infrared led lights up.  This is possible because unlike the human eye, webcams can still see infrared light even though they may have infrared blocking filters in place.  I could also use a multimeter set to the current range, and activate the remote by putting the probes on either side of the black contacts – I did this to verify that the microcontroller was sensing the contacts currently.

Now this reminds me, the Samsung TV remote control in the lounge room was also playing up.  I had a universal remote control lying around that I reprogrammed for the Samsung TV, maybe I should look at the failing remote control!  Oh well, I will leave it for another rainy day.

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Repair.IT – Repeller Car Alarm Remote Control

Most recent cars have some sort of remote control, usually to allow central locking and or activate the inbuilt security, engine inhibitor, etc. Cars from more than 10 years ago, might have central locking, but a lot of them didn’t. We have always added an after-market security system, which in the Honda Civic was a Repeller Car Alarm, fitted by the car dealer. These car alarms and keyless entry system usually rely on a key fob remote control that disables the alarm and unlocks the doors. Generally there is a battery inside that needs replacing from time to time. Don’t you just hate it when you try swapping the battery and the key fob still doesn’t work? Usually that is the time to use the spare remote, but what do we do with the one that isn’t working? That is what I had to do, a few weeks ago, to use the spare remote – I didn’t have spare batteries, but at least the spare remote works.

Most of the time, the electronics in the remote control or key fob are very reliable. They have to be, as they are carried in pockets with all sorts of items such as keys and coins. Many times they are dropped on the pavement – how often have you fumbled with the car keys and dropped them in the night time?

So what could go wrong – usually it is the switch that is failing. The simplest way of checking this is to open the key fob or remote control. Generally it is held together by one or two screws, then the housing comes apart. A 12V battery is usually found inside, depending on the car – I know some manufacturers use coin batteries, which don’t last long but is easy to replace. If the battery contacts look a bit green, then the battery has been leaking and the contacts will need cleaning, otherwise they will be covered in an oxide that has a high resistance which can prevent the remote from working. On the small circuit board, there is likely to be at least one switch, quite often two or even three. I didn’t have spare switches as these are surface mount and quite small, 6mm x 3.5mm in size, and 2.5mm tall – I did find them on eBay so ordered some and waited for them to arrive.

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The above photo shows the circuit board with the two switches, the red button is what is pressed when you press the rubber knob on the key fob. The white one is one of the replacement switches that arrived this morning. If you press the centre of each switch slowly, you should hear or feel a small click when the switch is activated. On my remote there are two switches, bottom one is to lock or unlock, and the top one is a panic switch – pressing the panic switch sets the alarm off, which is handy if someone is bothering you or trying to steal your car. I don’t think many remotes have this duress switch, but it can be handy at times. The lock/unlock switch doesn’t click which means it has more than likely failed.

If you have a multimeter, you can set it to measure resistance, then touch the probes onto each switch contact and press the switch – it is easy to say, but hard to do in practice. My switch is 6mm long, so after putting the probes on the switch, I need to use a small screwdriver to press the switch button. In my case, the resistance drops briefly but does not stay low, which confirms that the switch has failed. I can get it to stay low by pressing quite hard, but if I relax a little, it goes back high resistance. Ok, so to replace the switch.

I could use my hot air rework station to remove this switch, but I happen to already have a smd rework iron, which has tweezer tips. It is a simple matter of waiting a minute for the iron to heat up, then using the iron, clamp on both switch contacts, wait a few seconds, then lift the switch off the circuit board. Heating the contacts is fine, but when clamping on the switch, it does melt the switch plastic a little. To solder the replacement switch back on, we can do the same – but it is easier to use a conventional soldering iron since I need to hold the switch in place, solder one contact first, then solder the other end.
The replacement switch cost a princely sum of $2 for a packet of 20 – good price. I could have bought one if I could find a local supplier, but it would have cost a few dollars, so now I have 19 spares. Anyone need a switch?

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The photo shows it soldered in – yes, I know it is at a slight angle, but it should be fine. I tested it and it is working better than the original switch. However, during testing, the battery started to die. It did unlock and disable the alarm, but I could not get it to lock, unless I waited a few minutes for the battery to recover some charge. But at least the switch replacement is working, so now, I can order a couple of spare batteries – or maybe 5 because 5 costs less than buying 2 – how does that work?