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SERVICEMAN'S LOG Two devices what failed th’idiot test Dave Thompson Murphy’s Law (the real one) says: it’s impossible to make anything idiotproof because idiots are so ingenious. Or to put it another way, you make it idiot-proof and then they make a better idiot. This seems to be the case with both the items I repaired this month. In each case, the user (or one of their family members) managed to break it by doing something you’d think it would be designed to cope with. A while ago, a customer picking up her PC from my workshop noticed a few of my electronic bits and bobs lying around. She asked me if I knew anything about blood glucose monitoring devices. I immediately responded that since customers bring them in all the time, I was an expert at repairing them, and I knew them inside and out. Actually, sorry, that’s a lie. What I really said was no. While I had seen a few from afar, I had never played with them to see what made them tick. I decided to gloss over this technicality, though, and instead asked what the problem was. She said that as a diabetic, she 76 Silicon Chip needed such a machine to check her blood sugar levels. While her older, basic model still worked fine, she had shelled out a considerable amount of cash on a new, more sophisticated version, which she couldn’t get to work correctly. Perhaps I could have a look at it and see what I could do. Well, you know me, I had to at least have a go... When she brought it in, I was a little shocked at what she reportedly paid for the monitor. Though it looked like a quality, well-made unit, and came in a very nice travel case, there just wasn’t that much to it to justify the huge price tag. Having said that, if it worked as intended, it would be an ideal tool for managing her diabetes. The blood sugar monitor is a small, hand-held unit about the size of a pocket watch, with a Australia’s electronics magazine large, clear liquid-crystal display taking up most of the front face. On the top edge of the case is a receptacle for removable test strips. On the right-hand side of the case is a small sculpted gap, which looks like a socket for some kind of expansion module, and on the bottom edge is a mini USB port. That’s pretty much it; there are no switches or any other features to complicate things. This unit can connect via Bluetooth to a smartphone (or Bluetoothequipped laptop/PC), or to a PC via the USB socket. The smartphone app siliconchip.com.au Items Covered This Month • • • Two faulty Blood sugar monitors Olympus camera with a smashed viewfinder iPhone 5S battery replacement *Dave Thompson runs PC Anytime in Christchurch, NZ. Website: www.pcanytime.co.nz Email: dave<at>pcanytime.co.nz and the downloadable software for the computer (both accessible via a QR code included in the package) do pretty much the same thing, ie, save a record of all readings gathered by the device and present it in a graphical format. This enables the user to track their blood sugars, to see at-a-glance what’s happening, making things a bit easier to manage. It is a clever little device. But it didn’t work, and as it was purchased over a year ago, it was out of warranty. Most of these monitors operate in much the same way. The test strips look like a small rectangle of plasticcoated PCB material with exposed contacts at one end and a sensor track running down the middle. One is inserted into the slot at the top of the device and this action powers the machine on. A drop of blood from a pricked finger is presented to the tip of the test strip, and this is drawn down the centre track by capillary action. After a short countdown, a blood sugar reading is shown on the display. Usually, the monitor loses this information when the strip is removed and the device powers off, though with this model that data can be shared to a phone or PC. A lucrative business model Some of these machines can read both glucose and ketones levels. As these tests use different test strips, there has to be a way of telling the machine which strip is being used. The way they accomplish this is by plugging in a module, which looks very much like a USB dongle for a wireless keyboard or mouse, into that PCB socket I mentioned above. When a customer buys a container of test strips, a module is included siliconchip.com.au that is designed to work only with that particular monitor and set of strips. This is how the machine knows what it is measuring, and in this way, the manufacturer can guarantee reasonable accuracy. Each batch of strips and the module carry a unique identification number, and as long as these all match, the monitor readings will be as accurate as a home-use machine can get. So you can use one strip and module to measure blood glucose, then swap the module and the strip and test for ketones. Mind you, quality test strips aren’t cheap. I get the feeling that manufacturers of blood monitors took a leaf from the inkjet printer manufacturers’ playbook; they must make most of their money from sales of the consumables. And just like an inkjet printer, you can’t use test strips or modules from company A in the monitor made by company B. Clearly, there is big money to be made in health products, and all power to the people who design and market this stuff. But diabetics (here in New Zealand, at least) are offered little to no government subsidies for medical appointments, or any of the kit they need. It seems rather unfortunate that they charge as much as they do. But regardless of cost, no device is any good if it doesn’t work. In this case, the customer reported that it powered on when a test strip was inserted, but did not detect the strip module. The monitor was not detected when plugged into a PC via the USB cable either. I suspected that these two problems would have the same cause. The first thing I did was check the battery. There have been many times I’ve swapped cells out of a unit, to check whether it just needed a fresh battery, only to find that the cells I put in were already dead! Convenient though this solution may have been, both of the CR2032type lithium batteries (20mm diame- ter, 3.2mm thick) measured a healthy 3.1V on my analog multimeter; more than enough to fire it up. Opening it up was easy enough; a couple of tiny screws hidden beneath rubber ‘feet’ hold one end of the back cover while a clip arrangement holds the other. Once open, I could see a potential problem straight away. Of the four pins for the removable test-strip module, which is simply a set of exposed pins, two were bent. With the module in place, these pins weren’t making contact. The alignment of the module depends on how it is inserted into the cavity in the side of the case. Like a USB connector, it can only go one way. But given the lack of an actual socket frame or guide the module should line up with, it is easy to insert it cock-eyed. It looked to me that this is what happened. If it were forced in the wrong way around, that would explain the bent pins and lack of function. You’d think the manufacturer would have considered that and offered some protection against such a simple mistake ‘bricking’ the device. Luckily, straightening the pins was no real problem. I just had to be super-careful not to bend them too many times; this type of material is easily work-hardened, and it will break if pushed too far. I prefer to use tweezers for this sort of job because they prevent me from exerting too much pressure on the metal. I try to flex the pins only far enough to line them back up, and take great care not to overshoot and have to bend them back the other way. That is a sure-fire way to snap something off. This was a simple straightening job, and when finished, I immediately plugged in the module and made sure everything worked before buttoning it back up again. When I described what I found to the client, she recalled her teenage son had assembled the monitor when she first got it, and it was most likely Servicing Stories Wanted Do you have any good servicing stories that you would like to share in The Serviceman column in SILICON CHIP? If so, why not send those stories in to us? In doesn’t matter what the story is about as long as it’s in some way related to the electronics or electrical industries, to computers or even to car electronics. We pay for all contributions published but please note that your material must be original. Send your contribution by email to: editor<at>siliconchip.com.au Please be sure to include your full name and address details. Australia’s electronics magazine December 2019  77 he who had first inserted the test-strip module incorrectly. It was relatively simple to download the app into her phone, and I installed the PC program and drivers from the links provided, so I could check that the machines all talked to each other. To my knowledge, she is still using it and has reported no further problems. Repairs always come in twos I’m no stranger to odd coincidences. Back when I was a poor apprentice, my tooth broke. Later that day, I discovered enough money to cover the bill to fix it in a jacket pocket I hadn’t worn for years! Other times, I’ve thought of clients I haven’t heard of for years, then they call the next day, wanting work done. I’m busy figuring out how to capture and bottle this phenomenon and when I do, you’ll find me kicking back on Easy Street! So, not a week after that last repair, another client asked me about fixing a water-damaged blood sugar monitor. I thought it strange I’d never fixed one before and now, within a week, I have two coming through the workshop. This monitor was a very basic model, slightly older than the previous one, with fewer features and predominantly used for measuring ketones in the blood. This is useful for those on a socalled ketogenic diet – a high-fat, low carb diet which is used to get the body to burn ketones for energy instead of carbohydrates. The things we learn as servicemen! In order to know if the diet is working, many people turn to electronic blood monitors that can give reasonably accurate readings of blood ketone levels. If these numbers are maintained, fat loss (and the weight-loss that goes with it) is the typical result. This customer was standing near the kitchen sink with their monitor and had accidentally dropped it into the dishwater, whereupon it immediately ceased working. Despite putting it straight into the hot-water cupboard and leaving it for the past month, it still didn’t work. Liquid-damaged electronics are tough to diagnose. Sometimes everything starts working again after they dry out; other times, the device remains dead forever, regardless of whether a bag of rice, a hair-dryer or some other method is used to dry it 78 Silicon Chip out. Two identical devices could be submerged in the same circumstances with different outcomes. I typically explain this to the client and let them make the call as to how we deal with it. Given that you can pick up very cheap blood monitors out of China, it makes no sense to throw a whole lot of money at repairing an older, faulty one. So we have to decide how much effort (and money) it’s worth expending on a repair before we pull the plug and chuck it in favour of a new one. The customer had a new box of 100 test strips made specifically for this device, so it made sense to put a nominal amount of cash into at least trying to repairing it. Another easy fix Opening it was very similar to the last monitor, except this model used four small screws to hold the cover on. Once the back was off, I took the board out and checked under a microscope for obvious signs of water ingress. Though this was a relatively inexpensive model, they sure packed a lot onto the PCB. It was made with almost all surface-mounted components on a double-sided circuit board. Water under any of these components could cause it to malfunction, and getting any residue out could be a major headache. But it was surprisingly dry inside, and I couldn’t see any evidence of water ingress. So why didn’t it work? I started at the beginning, or at least the electrical beginning, with the contacts at the top where the test strip connects. On closer inspection, these looked very oxidised and patchy. While they appeared to be gold-coated, I guessed the actual gold content is a little lower than contacts in a higherquality monitor. Whatever other compounds were mixed in with it had tarnished. I used isopropyl alcohol and a light rub with my fibreglass-bristled cleaning pen to bring them back to the gold standard. I also checked the module pins – the module was still in place, and these too had a look of intermittency about them. Cleaning that was a little tricky, especially the contacts inside the module, but a few strips of alcohol-soaked tissue flossed carefully among the various pins and contacts had them looking better. Australia’s electronics magazine I installed new cells and broke out a fresh test strip. This time when I put it in, the display powered up. It looked a little blotchy, but it worked and displayed legible characters, so that was a lot more than what it was doing before. I pricked my finger and fed the test strip; apparently, I wasn’t in “ketosis”, but I didn’t expect to be, so the reading was most likely accurate. To be thorough, I removed the cells and module and put everything in a bag of rice in the airing cupboard for a week, in the hope of leeching any remaining moisture out of the parts before returning it to the customer. As far as I know, he is still using it, working his way through the test strips he has left. If he still wants a new monitor after that, he won’t feel so bad about wasting the money spent on strips. Olympus camera smashed viewfinder B. W., of Sydney, NSW, had that dreaded moment where he accidentally dropped the bag containing some delicate electronics and heard a nasty crunch. Luckily, he had a piece of donor equipment and the patient survived the operation... It all started when I was hurrying along a Melbourne train platform with my lovely old Olympus C8080W in its siliconchip.com.au carry bag, the strap over my shoulder. The strap slipped off my shoulder and down it went onto the pavement. My first thought was that the glass in the wide-angle lens could have smashed on impact. On opening the bag, I could see that the digital viewfinder glass was cracked and the LCD screen behind it was showing tell-tale black areas where the liquid crystal had leaked out. While the bag is padded to handle short drops and other impacts, unfortunately, the lens cap had been pressed into the viewfinder, resulting in this damage. The camera has a second internal viewfinder but while this worked in playback mode, it no longer worked when I tried to take a photo. Perhaps the damage was shorting something out. Regardless, I would have to fix the smashed screen. I had another identical camera which no longer worked but the screen was intact, so I decided that this would become a donor. My pal Dick from the Yahoo Olympus Camera Group sent me a pictorial breakdown PDF of the camera internals so that I could see the disassembly steps required. I would need a set of tiny screwdrivers, tweezers, close-up eyeglasses, good lighting and a cautious approach to succeed. I started to take the camera apart and it all went well. Finally, I had the LCD screen out of the articulated holder but still connected to the feeder PCB hiding just inside the holder, with two flat ribbon cables still firmly attached. The next step was the most delicate; if I made a mistake by forcing any of these fragile and tiny components, the whole repair and the future of this camera could be in jeopardy. The ribbon cables were sensibly attached to connectors on the partly hidden PCB, still inside the articulated carrier. I gently nudged them as best I could but they would not budge and there was nothing obvious to pull or push on the sockets to remove the cables. I had to turn to the internet for answers. I found the following YouTube video from a German guy who was doing just what I needed to do, on the same model of camera. His lighting was poor and the camera angle was not great but just once, he showed a pull of a locking black bar across the top of the socket and the ribbon cable then came free! See: http://youtu.be/ uyCVRY9Z1h0 So that was it! Now with confidence and armed with a dentist’s hooked tool, I ventured into the hidden cave of the PCB and hey presto, the socket opened up, allowing the ribbons to slide out and the donor ones to go into place with ease. I then re-locked the ribbons into the sockets, re-assembled the camera, inserted the battery and switched it on. Hooray, the viewfinder was operational! I then just had to clean the display, re-fit the protective glass panel and then make some changes to my carry case so this sort of damage will never happen again. the back and sides of the phone. It all felt “squishy”, so I suspected that the battery had become swollen and was pushing the screen out. My wife had also remarked that the battery was tending to run down quickly, which strengthened the swollen battery hypothesis. A swollen lithium-ion battery is a fire risk, so until a new battery could be fitted, I found a large Pyrex bowl that we could put the phone in while it charged, to prevent it from igniting anything else if it caught fire. The Apple store charges $119 to replace the battery in this model, which is more than the phone is worth, and it probably couldn’t be done while we waited. There are various phone repair stalls in arcades and shopping centres, and they charge about $35 to replace an iPhone battery, but I decided to have a go at it myself first. Despite some misgivings, I bought a new battery from eBay which was advertised as “brand new genuine original”. It cost just under $18 delivered, including a full set of tools and the allimportant adhesive strips, and I had it in less than two days. I was pleasantly surprised at the quality of what I received. The iFixIt.com guide for iPhone 5S battery replacement estimates it will take between 30 minutes and an hour. It took me closer to two hours, but that’s because I read every single comment that individual fixers had made iPhone 5S battery replacement A. P., of Concord, NSW obviously loves a challenge because he had the option to pay someone else a small fee to fix his wife’s phone but decided to do it himself anyway. Luckily, it worked out well in the end... My wife recently told me that her iPhone 5S was showing “rainbow colours” wherever her finger touched the screen. I took the phone out of its protective case and observed that the bottom edge of the screen was pushed slightly out of the aluminium shell that forms siliconchip.com.au Australia’s electronics magazine December 2019  79 on every single step; I’m glad I did, as they almost certainly saved me from breaking something. The first step when the battery is swollen is to discharge the phone’s battery to no more than 25%, to minimise the risk of the battery catching fire if ruptured. The phone was at 83% charge when I started, so I set the screen to full brightness, turned on the torch function, and set AutoLock to “Never”. I used the time while the phone battery was discharging to read through some of the steps of the repair and the associated comments, but after half an hour and with the battery still at over 50% charge, I became impatient and powered the phone down, ready for the dismantling process. The iPhone 5S case consists of a one-piece aluminium tray which forms the back and edges of the phone. The front panel squeezes into the tray and consists of the display, its narrow plastic bezel, and metal clips which grip the inside edges of the tray. The tray holds most of the electronics and hardware of the phone, including the battery. There are some flat cables near the top of the phone that connect the display and front camera and sensors to the motherboard. There is almost no slack in these cables, but the display can be pivoted up 90° with these cables still connected, giving pretty good access to the interior of the phone. There is one other flat cable, near the bottom of the phone, that connects the home button/Touch ID sensor to the motherboard. There is enough slack in this cable to allow the bottom of the display to be lifted a couple of centimetres away from the tray, which gives sufficient access to disconnect the cable from the motherboard. To start with, I removed the two pentalobe screws at the bottom, on either side of the lightning socket. The home button cable is particularly prone to being torn in this model because the front panel is meant to be quite a tight fit in the tray and can come away suddenly. If you damage the cable, you have to replace the home button, but only the original home button is “keyed” to the motherboard so you’ll lose the Touch ID feature. As I started pulling the two halves apart, I noticed that the display was separating from the metal clips. The iFixIt crowd-advice for this sit80 Silicon Chip uation is to ease the metal clips out of the tray using two plastic tools shaped like guitar picks. These were supplied with the new battery, and I found that by using a combination of fingernails to do the pulling and inserting the picks into the gaps to prevent them from closing up, I was able to ease the bottom of the front panel up out of the tray without too much trouble. The next step was to remove the clip that secures the home button cable’s plug in its socket on the motherboard. Having removed the cable, I discarded the clip as I realised that it would be awkward and risky to reinstall it. I read comments from those who had done likewise and found that the cable nevertheless remained secure. I then popped the home button cable off the motherboard using the corner of a spudger and was able to lift up the bottom of the front panel, with the remaining flat cables at the top of the phone bending like a hinge. The battery was now fully exposed, and I could both see and feel its swelling. The new battery, by way of comparison, was perfectly rectilinear. At this point, iFixIt guides you to remove the display, touchscreen and camera/sensor cables from the motherboard, thereby separating the front panel from the phone. This would have required dealing with another four tiny screws in three different sizes (1.2mm, 1.3mm and 1.7mm) that must all be put back in the correct holes during reassembly, or else risking permanent damage to the motherboard. I felt that I had good enough access to remove and replace the battery without bothering to disconnect these cables, so I skipped ahead to the battery removal. The battery connector is secured by a screwed-down clip. This was easy to remove, and I then used a spudger to pop the battery connector off the motherboard. Even this apparently easy step has a gotcha: it is difficult to see whether you have inserted the spudger between the battery connector and its socket, or between the socket and the motherboard. Prying too hard when the spudger is under the socket is liable to damage the motherboard. The next step is to remove the old battery, without using sharp metal tools that could puncture it. The battery is secured to the tray by a couple Australia’s electronics magazine of double-sided adhesive strips. These strips emerge from the lower end of the battery and join to a pull-tab that is usually tucked into the space at the lower edge of the battery. You pull slowly on the tab and the adhesive strip narrows and pulls away from the space between the battery and the tray. To make removal of the adhesive strips in this phone easier, iFixIt suggests putting the phone on something warm to soften them first. I microwaved a damp face flannel in a plastic bag and laid the phone on top, then teased the pull-tab out from the gap at the lower end of the battery. There is a small hole in the tab, and the tiny Philips head screwdriver that came with the battery let me pull it out far enough to be grasped in my fingers. Then I pulled gently on the tab, just enough to see the two white adhesive strips start to come out from under the battery. At this point, I snipped the tab in two using nail scissors so that there was a separate tab for each of the two strips – this lets you deal with each strip separately. Next, I pulled a little bit more firmly on one of the tabs. The trick is to pull firmly and constantly, but to be patient. It also helps to continually work your fingers along the strip towards the battery as the strip stretches, as this minimises the chance of the strip breaking. In my case, both strips snapped before they were completely out, so I was left with the unenviable prospect of levering out the battery while avoiding bending it too much lest it rupture and catch fire. To do this, I used a plastic spudger and used the same principle of firm, constant pressure and patience. By applying not quite enough force to perceptibly move the battery, and waiting, the battery came free without being deformed. Once the battery was out, I was able to clean up the remains of the adhesive strips. The replacement strips have blue protective film on the side that is to be installed facing the tray, and pink film on the side that faces the battery. After sticking the new battery into the case, reassembly was straightforward and the front panel now fit precisely. The phone works fine with its new battery, and the rainbow colours surrounding fingers touching the screen are gone. SC siliconchip.com.au