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 – Samsung CLX-3305FW Colour Multifunction Laser Printer

Actually, as a species, human beings are quite tolerant.  What do I mean by this?  You print something and go to the printer and it isn’t there.  You look at the screen and you see the dreaded “Paper Jam”.  So the process is pull out the paper tray, no stuck paper – put it back in.  The message is still there.  So open the front of the printer where the toner cartridges are, pull out the cartridges one at a time – no paper stuck behind, so replace the cartridges, and close the front panel.

The message goes away, and the printer starts humming and the printout comes out.  Now this can happen for a while, until such time that even doing this doesn’t help.  Oh, there is another door at the back of the printer, so open and close this one, and sometimes this helps and the printout comes out.  Eventually, it gets to the stage where the paper jam happens almost every time you try to print.

We could have lived with this problem for months, because once we get our printout, we forget about the problem.  This is what was happening to my Samsung CLX-3305FW Colour Multifunction Laser Printer.  It hasn’t had a lot of use, from memory it is still on the second box of paper, so what could be wrong with it?

After a bit of googleing – (or is it googling?) it seems that the culprit is the paper pickup roller – which with printing and/or age, gets a bit smooth from the paper dust and other environmental issues.  Fortunately, I was able to find a service manual for this printer, and the diagnosis also appears to be the pickup roller.

Hence, two days ago, I decided that it was time to have a look at the culprit.  I removed the toner cartridges and stacked them neatly with a piece of newspaper on top to stop dust from getting onto them.  This was a precaution since it is easy to take things apart and then it sits there for days, weeks,…  Continuing, with the paper tray removed, I put the printer on its back – and just managed to stop the scanner lid from crashing down onto the toner cartridges.

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With the printer in this position, I could see and reach the pickup roller quite easily.  The roller is locked in place by a white piece of plastic, which is held by another black bit of plastic.

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Here is a closeup of the pickup roller.  By unhooking a tab on the black bit (where the dark line is), I could slide the white bit to the right, thereby giving some room for the roller to disengage, then spin it around 180 degrees and it comes out.

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You can even see some paper dust.  Then the pickup roller comes apart, by unlatching the two black bits.

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I brushed the rubber tube, then decided to turn it around by 180 degrees and use the surface which was not exposed as the new pickup surface, then put it back together.  Replacing it was just the reverse, put it back onto the shaft, spin it around, then lock it in place by moving the white and black bits to the left until it locks.

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So, there it is, another repair done.  Ok, so did it work?  It did say paper jam on the first page I tried to print, but then did the rest of the pages ok.  So time will tell if this is a permanent fix, or if I need to do more.

 

Repair.IT – Highgate wall light with PIR motion detector

Here is something that was on my bench for repair. A Highgate OL7664BK outdoor wall light with PIR motion detector. It is a nice light made from black metal housing with glass pieces which had been installed at a sister’s place during a small renovation, and then failed to turn on, a few months later.

After making contact with the supplier, a replacement light was sent out. In due course, the light was then replaced, and I was given the faulty unit – perhaps I could Repair.IT and get it working again.

After opening the light housing where the sensor is located, I found that the sensor unit is a small black box with the PIR on the outside and three wires going into it. Brown, Blue and Red – guess what these would be? Fortunately, they also went to a terminal block which was marked. Brown and Blue are standard colours for Active and Neutral, but Red’s marking was an X – ok, meaning switch.

Sure enough X went to the Active of the light socket, with Neutral being the common for the light socket. Also I noted that there was also a ground wire terminating onto a stud on the metal housing – that is very good indeed. Now, the light is still usable if we wish to use it just as a standard light fitting, without the PIR sensor by just wiring the input wires to the active and neutral of the light socket.  However, I am interested in how to fix it.

The small black box was sealed, but nothing a rubber mallet couldn’t solve, so eventually the seal where it was either glued or plastic welded – came apart and I could get to the interior.

Inside was a small board that was connected to the separate PIR sensor board. Often the question I get asked, is how do we determine what the fault it.  Generally we will know something about the device, in this case – it is a switch that turns on or off the light.  The PIR sensor board does the sensing, so it must then use the small board to switch the light.

Usually this involves an optical isolator which is usually in a small 4-pin or 6-pin package.  This optical isolator, or opto isolator will then somehow connect to a switching device, which is usually a triac.  This small board contained a MOC3023 which is a known optocoupler with a triac driver output.  From this chip, it connected to a triac via a small limiting resistor.

I examined and determined that a Triac had failed. In additional the small limiting resistor of value 200 ohms had also gone open circuit.

Likely what had happened was that the Triac had failed, and the ensuring high voltage caused excess current to flow through the tiny resistor which then failed. Or it could have been the other way around, but the resistor is slightly discoloured which meant that it had gotten way too hot.  In this photo, the resistor is the one near the top left.  The marking shows 201 but the 0 is a bit marred.

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The marking on the Triac was a BT136-600E. My local Element14 supplier had these in stock, for around $1.26 but then ordering this by itself  plus the resistor would incur a delivery fee much larger than the total.  Since this was a charity repair, I elected to buy these parts on eBay.  10x BT136-600E’s were $1.86 delivered, so this was a good deal.

The resistor was a 200ohm surface mount version in a 1206 package – I managed to find a good supplier that would give me 100 pieces for $1.34 delivered.  In the case of eBay, why buy 1 when you can get more for a similar price.  It leaves me with lots of spares for future repairs.

The BT136 was easy to remove, just using my desoldering station – it was a matter of minutes to desolder each pin and remove it from the board.  Similarly, but using a SMD tweezer soldering station, the resistor came off in a few seconds after heating.

Once the parts came in, which was a few weeks in most cases – I soldered the replacements into place.  Here I am showing the replacement resistor with a good 201 marking.

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Here is a view of the top of the board, showing the bad triac on the board mounting.

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In case you are wondering how small a 1206 resistor package is, it is 3.2mm long and 1.6mm wide, just don’t drop it on the carpet, since you may not find it again.

Oh, by the way, once assembled and wired up on the bench – it does work.  The light would light up when I walked near it.  Another successful Repair.IT

Repair.IT – Kleenmaid TO500X Electric Oven – again

This is a followup to the previous article on the Kleenmaid TO500X Designer Multi Function Electronic Timer Oven.  Remember that after the repair, it was working, but after baking a set of frozen pies on one weekend, the next weekend – it stopped working again.  The symptoms were different this time.  The oven lights inside will work, but no heating or fans would operate.  I thought at first that it was the thermostat, since this controlled the power to the heating elements in order to turn them off to maintain a set temperature.

I switched off the power, and checked that the thermostat was in fact … working, just like last time I checked.  Ok, so scratch that idea – what else could be wrong.  Eventually after some thought and research, I was reading the oven operation manual, which suggested that on some models, there was an oven door switch which would cut the heating if the door was opened.  Yes, this oven did have a door switch, which used to cut off the heating when the door opened, but I remember that recently it had not been stopping the heating.  There is a red indicator light that shows when the heating elements are on, and in the past – this went out when the door was opened, but in the last few months, it seemed to not go out.  Maybe this could be the reason.

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So, open up the housing and locate the door switch that was on the left side, check for continuity, and nothing – even when the button was pressed all the way.  This had failed so checking for a replacement – Metalflex MS-385 seems a common part, but this one was shaped differently.  The local oven parts stores didn’t seem to show this as a spare part – so maybe I can just bypass it, like I did with the relay.

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After I had written the previous article on this oven, I remembered reading that this particular model would disable the power if the clock was not set – as a fail-safe.  By applying the power and setting the clock, I could hear a click from the clock area.  Perhaps the relay was now being turned on.  But then – how to explain the previous problem?  Unless the door switch had decided to become intermittent, and sort of arc’ed over – maybe the timer electronics detected this as a fault and cut the relay.

I had tested the clock board and controller out of the housing and had not been setting the clock, so the relay would not have been turned on.  Bypassing the relay would allow the power to be available independently, so maybe the relay is working again, after a power reset.  To test this hypothesis, I decided to remove the bypass on the relay and just have a bypass on the door switch.

I reassembled the door switch mechanism and then closed up the oven, and went and replaced the fuse that I had pulled out in order to remove power to the oven.  The oven clock was now blinking and after setting the time – a couple of seconds later, I heard a click which could have been the relay turning on.  I used the control to turn on the light, and the light came on – fantastic.  Selecting the fan, and yes – the fan would spin up.  Next, turn the thermostat, and the thermostat indicator light came on – meaning that power was being applied through the thermostat.

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Well that is good, I have a working oven again – except that the door switch is no longer operational – but it was an optional feature anyway, which helped for safety – but most of these ovens don’t have one.  It looks like this oven is now repaired, again – and hopefully for good.  In the meantime, I will see whether I can locate a suitable replacement switch to restore its full function.

Repair.IT – Air Compressor

Some months ago, I needed to paint the wooden deck in my backyard – yes, the one that I built – did I write about it? Anyway, the oil that I used was starting to wear off. A colleague from work suggested that I use a spray gun to make the job go faster which I thought at the time was a great idea. I had already been asking around for a new oil to buy, but the final word was that since we had already used the Cutek oil, that we should continue with that oil.

My colleague had lent the air compressor to another colleague, who in due course finished with his work, and I was able to get the compressor, a long coil of air hose, and a spray gun attachment. On the next available weekend, I hauled everything to the backyard, connected the power to the compressor, and switched on. At this point all I heard was a slight clicking sound coming from the compressor, so switched off. Switched on again, and still the clicking sound, which doesn’t quite sound like a motor turning, but more like a stalled motor.

I shut the power off, then could see the rotor through the grill and could turn the rotor with a long screwdriver, so that means that the motor hadn’t siezed up.  After a bit of head scratching, I decided to open up the cover to expose the motor. An air compressor is essentially a motor that turns a compressor that pushes air into a container until it bursts – or actually, until a pressure is reached whereby the motor is switched off before bursting point.

The motor is just an average ac motor, usually one that is either a capacitor-start motor or a capacitor-run motor – which means that if it doesn’t work, usually it is because a capacitor has failed. So essentially, this capacitor failed between its last job and in transport to my home – what luck. So, opening the cover should allow me to see the capacitor, remove it for checking, and then obtain a replacement.

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As Murphy would have it, part of this was easy and also not easy. The capacitor had some hard black plastic foam glued to it, to stop it from rattling against the case, but the foam had hardened to be almost rock-like – it had dented the side of the capacitor, and as luck would have it, has also covered the part that shows what size the capacitor should be. I measured the capacitance and it was very small, almost unmeasurable whereas I would expect something in the 10-30 uF.

I then used a hacksaw to cut the black foam, and eventually exposed the label enough to show that it is a 35uF capacitor, which was also not an easy one to find. After some time, I decided that I could get a 30uF and a 4.5uF and connect them in parallel, to get 34.5uF which should be close enough, since most capacitances are +-5%.

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Here is my replacement capacitors wired together.

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And now, here they are mounted on the motor frame, which fortuitously had mounting points for two capacitors – great.  Once wired in, and cover replaced – switch on, and the sound of… a loud compressor running, ok – so pressure is not increasing and air coming out the bottom – the drain bolt needs to be screwed out to close the drain.  Try again – and finally, pressure increasing – and eventually, yes – it stops.  Great – another Repair.IT done and can get back to spraying some decking oil.

Repair.IT – Table Tennis Table Support Leg

I was at my local community centre before Easter. They have a number of table tennis tables which get pulled out regularly (almost daily) for people to play table tennis. With all of the use, and sometimes heavy hands, the tables are quite worn and have a few faults. One in particular had a broken support leg, which made it unusable. I had a quick look at it and thought that all it would need is a few brackets to fix the rolling support leg, and it could be as good as new.

I had a look at what Bunnings had to offer and spoke to the community centre about it and offered to fix it for the cost of the parts, which I estimated to be about $30-40. Then it was a matter of getting the parts, then on Thursday last week, I was able to get the leg removed to bring home where I can do the repairs.

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Here is the support leg removed from the table and separated into its various parts, mainly removing the wheels. The top section was welded but this is what had broken.

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A T shaped mending plate was the right size, two of these, one on each side, then a couple of right angle brackets for support. The metal is quite thin on the leg, only 1mm, so I had some 40mm square hollow steel section in my garage, so cut off about 30cm of it. This reinforcing tube which is 2mm thick would fit inside the horizontal leg, but because it is a bit smaller than the inside, would need some spacers to raise it to the top of the leg.

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Then additional spacers for the side, since I wanted to get it more or less in the middle of the hollow leg.

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Here I have fastened the reinforcing tube with four Tek screws. Due to the thickness of the tube, I decided to pre-drill 4mm holes where I would install the Tek screws for the right angle brackets.

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I decided that I should clamp it all together and mark out the holes for the mending plate for both sides. The drilling could then be done easily on my milling machine than with a hand-held drill.

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It was a matter of fastening a lot more Tek screws, and I ended with a leg that is much stronger than the original – maybe a bit of overkill, but not bad for less than $40 in parts. I need to wait until after Anzac Day for the community centre to open before I can install the leg and fasten a couple more screws, and also replace a number of nuts and various bits that were also missing.

If I didn’t help them with this, they would probably have to spend many hundreds of dollars on a new table which is probably not as good as the repaired table. They have some more tables for me to look at too!

Repair.IT – Overheating Presario SR5120AN motherboard

Remember two and a half years ago, approximately, I repaired my Compaq Presario SR5120AN motherboard which had a number of failed capacitors?  Ok, it was some time ago, so here is the link.

https://j0hn88.wordpress.com/2014/12/22/reveal-it-faulty-capacitors-on-presario-sr5120an-motherboard/

At the time, five capacitors had failed, but there were still four others of the same brand and size on the motherboard. I checked them with an ESR meter and they all passed. Fast forward to a month ago – I noticed that my computer cpu fan was getting louder, sometimes normal then suddenly high speed and this kept happening. I ran a utility to check the CPU temperature and it was …  99 degrees, wow! No wonder the fan was on turbos a lot of the time.

I shut down and took the computer apart to reveal the motherboard.

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Two of those same original capacitors were showing the symptoms of failure – see the bulging top and black spots. After some effort, I was able to remove these two capacitors, then replace them with the ones in that little bag – I originally bought ten of these 1800uF 6.3V electrolytic high temperature capacitors. I checked the remaining two on the board and they check out fine.

So, reassemble the computer, and power on – leave it on for a while, and I can see that the CPU temperature is sitting reasonably stable at about 80 degrees. This is still quite hot and would appear to be still abnormal. Since I still have three spares left over, why not just replace the remaining two capacitors and be done with it.

That is what I did – took out the other two capacitors, replaced them with new ones. While I was doing this, I checked the capacitors with my ESR meter, which showed that these two were still ok, but anyway I have new ones in the motherboard now. Once the computer was up and running again, leave it for a while and then it was looking good so I decided to run the Passmark Performance Test, which stresses out the computer.

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This is what the CPU and graphics card temperatures were during the test and then the cooldown period afterwards. The CPU maximum went to about 93 degrees but then back down and sitting stable at 54-60 degrees. This is amazing and shows that even though the ESR meter indicated that the capacitors were ok, replacing them reduced the average temperature dramatically. Why is that – maybe the capacitance has changed? Wait, I can check this!

Just over a year ago, I had bought from eBay, a Mega328 Transistor and component tester. I can connect the parts I have removed and compare with new parts.

These two are the failed capacitors. They appear to be back to back diodes with differing forward voltages.

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Here is a new one – my final remaining capacitor. The value is 1829uF, ESR is good, with Vloss of 2.5%.

Here are the two apparently good ones that I replaced. These also appear to be good as far as the tester is concerned, however replacing these two also brought down my average temperature of the CPU. Why? I don’t really have an answer for this, but maybe someone has.

Right now as I am writing this, my CPU temperature is sitting at around 80 degrees, with CPU load at about 85% since my antivirus scan has been running for some time, but certainly nowhere near the 99 degrees at idle that it was a month ago. It has been a few weeks now, and all seems to be well.