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SERVICEMAN’S LOG Trail camera fun Dave Thompson Sometimes when you’re presented with a faulty device with no obvious symptoms, you have to take an educated guess and repair the bit you think is most likely to fail. That’s what I did this time, and while it was a bit of a circuitous path, it eventually led me to the right conclusion. Sometimes, you just need to trust your gut instinct. Remote cameras have been used in sports and wildlife photography for decades, but they have increasingly become both much more advanced and affordable recently. One particular use of them that has grown hugely in the last few years is in the great outdoors. Hunters, nature photographers and conservationists are all big users of so-called trail cameras (sometimes called hunting cameras). These devices use increasingly modern technology to allow users to ‘set and forget’ camera traps out in the wild that (hopefully) capture images and videos of animals or natural activity that is rarely seen. The basic idea is simple: set up one or more cameras in an area of interest, and anything that meanders past, day or night, will trigger the camera into action. Most of the latest devices can record both high-resolution video and still images, with the captured data stored on a built-in memory card. In some models, it is also transmitted via SMS/ MMS to a mobile phone. Most of these cameras also have night-vision capability, using arrays of high-intensity infrared LEDs to provide a wide area of night-time illumination, even in complete darkness. The advantages of this scheme should be obvious; a standard flashgun would work, but would scare off (not to mention temporarily blind) any detected game. However, the invisible-to-most-eyes infrared flash or flood would not reveal the presence of anything out of the ordinary to the quarry. I first heard about these cameras many years ago, after one of our cats went missing, and I looked into buying one because reported sightings were coming in. We wanted some way of knowing if he was turning up to these people’s places. He also may have been coming back home after dark. Either way, we wanted to know. I did my ‘due diligence’ and purchased a mid-priced unit from a reputable brand at a local retailer. This model had a 2-inch (5cm) screen for reviewing footage and a range of functions we’d likely never use, all in a relatively compact, camouflage-motif case. I had a good play with it before deploying it, and it lived up to the bumf. The photo quality was especially good, even in complete darkness, though this was monochrome – during the day, it took the usual full-colour snaps. Then again, one would expect decent quality with a purported 12-megapixel sensor and a fixed-focus lens. The camera used the older SD card format for data storage, and even a relatively-small 4GB card was enough for a lot of photos. However, if the video recording option was enabled, it used up the storage space pretty quickly, so I stuck with stills initially. Its battery life was good, but this model also had a ‘backpack’ battery holder, meaning an extra four AA-size cells could be fitted, giving the camera a significant amount of unattended operation capability. The whole idea is to ‘set and forget’ and come back in a few days, weeks or months to download what the camera has captured in the meantime. I soon learned that trawling through a thousand almost-identical images was a considerable time investment! Leaves, wind, birds, hedgehogs, cats, dogs, mice and bugs could set it off – and often, the image would show nothing but a slight ‘spot’ in range of the PIR sensors. Ah well, we don’t get anything for nothing! Enter the customer My point – as usual, a long time coming – is that a customer recently brought in one of these cameras for me to look at. Ironically, he’d brought one into my workshop a few years previously (a considerably older model) that he’d been given but did not work. When I cracked the case open, I could see why; someone had stored it long-term with batteries in place, and they had 86 Silicon Chip Australia's electronics magazine siliconchip.com.au Items Covered This Month • • • • • Messing around with a trail camera The dilapidated pair of touch lights The compact fault whisperer Follow-up to Clenergy 1.5kW solar inverter Repairing a lathe’s motor speed controller Dave Thompson runs PC Anytime in Christchurch, NZ. Website: www.pcanytime.co.nz Email: dave<at>pcanytime.co.nz Cartoonist – Louis Decrevel Website: loueee.com leaked – badly. The entire area of PCB beneath the battery holder had corroded away, and the device was completely dead. Even if I could see any tracks (or remains of tracks), it would have been impossible to repair them. He was philosophical about it – he’d been given it after all – and used that as a premise to buy a fancy new one. It was this new model that brought him back this time. It had worked hard for several years, usually mounted out by a run on his rural property, monitoring for feral cats and any other predators that were breaking into the run and decimating his chicken population. This had become an essential piece of kit in preventing animals from poaching his stock, and he was keen to get it back to work. This meant that it had spent all of its working life sitting in weather, ranging from far below freezing to baking in the scorching summer heat. I was surprised it had lasted this long! I hated to think what it was like inside, IP66 rating or not! The problem was that while it appeared to be working (various lights on power-up etc), it was not taking any new photos, the last one having been several weeks previously. Something had happened in the meantime, although on careful questioning, he did say that he had changed batteries ‘around’ that time. This was a clue, perhaps. Getting it open was no challenge. Six screws held it all together, and after removing them, I could gently ease the case apart. It was pretty tight, which was caused (it turned out) by the weather seals holding on tightly. Each screw turret had a rubber seal between it and the back of the case, and there was a large, embedded ‘o’ ring in a channel around the very edge of the case. This is flattened slightly by the screw pressure on the other half of the case, and should have kept the inside weatherproofed. I was expecting carnage inside, given its working history, but it was actually pristine. That weatherproofing did its job well! The only real possibility of water/environment ingress into the case would be through the hinged access panel. When the camera is sitting normally, it is at the very bottom. That puts it out of any real weather just by being where it is, and that trapdoor has a seal on it as well. Popping that hatch open reveals all the main controls, including an Off/On/Test switch, external power and video out connectors and mini-USB and SD card sockets. The screen is on the rear of the device, covered by the backplate in normal use, and below that are membrane-style siliconchip.com.au shuttle buttons for manually taking photos or movies and for captured video and stills playback. This allows it to essentially operate like a standard digital camera. Usually, in ‘test’ mode, the screen is activated, and we can alter camera settings and preview captured data; but that was no longer happening. Turning the camera ‘on’ using that switch would usually result in a red LED embedded within the LED array flashing for 10 seconds before going dark, indicating the camera is ‘armed’ and ready to detect any movement. The delay gives the operator time to shut the hatch and exit the area without taking any accidental selfies. Pushing the switch further to ‘Test’ mode also fires up the red LED, and then a blue one next to it lights up when the two PIR sensors detect any movement. This allows more accurate positioning of the camera’s detection area, similar to a ‘walk’ test we do for home alarm PIR sensors. As I mentioned earlier, the screen didn’t light up in Test mode. Neither did the blue LED activate. All roads led to Test mode not being entered at all, and on top of that, even in normal operating mode, the camera no longer wrote anything to the SD card. Something seems fishy I suspected the switch itself. It didn’t ‘feel’ right when actuated, and as one of the very few moving parts, it was at risk of wearing out. Getting to it was not easy; the PCB, which is stuffed with electronics, sits sandwiched between the moulded battery holder and the hard-plastic back half of the case. Space is very tight, though the PCB screws and clips would be relatively easy to access with a small screwdriver once the battery holder was removed. Still, the battery holder – a separate and quite-complex plastic moulding – could only be removed once the power connections to the PCB were de-soldered. These connections were actually extensions of the battery spring connectors, and they were press-fitted into the plastic holder. I had to be careful not to go too heavy on the heat and melt them out of the housing! Some deft soldering iron work and pump/wick application soon had the leads out and clear; the holder assembly could then Australia's electronics magazine July 2022  87 be unscrewed and unclipped from the PCB. Now I had better access to the PCB screws and could take that away from the case shell. This gave me direct access to the switch. I was hoping it was the switch because, if not, there would likely be little more I could do with it. As is typical, there are no circuits or schematics available anywhere for these cameras and, even if I did have one, troubleshooting something with this many tiny SMDs is no fun at all. The other thing I had to consider is that a very similar – if not better – camera is available from my favourite online shopping site for under a hundred bucks. So any fix on this would have to be pretty easy and inexpensive to make it even worth repairing. Partly out of curiosity (and the Serviceman’s Curse, obviously), I wanted to see if I could get it working. The switch is a reasonably standard-looking triple-pole, triple-throw sliding type. As is becoming more usual, the metal outside case is soldered to pads on the PCB, along with the six soldered pins. Taking mounted components like this off a PCB can be a chore, especially on multilayer boards. That is, unless you don’t want them any longer, in which case just cutting off what we can with a Dremel or good side-cutters is the easiest way. Then it is just a matter of extracting the cut-off legs and whatever else remains behind. Rudimentary tests in-circuit weren’t that conclusive as to whether it was making the right contacts or not, so I decided just to cut the switch away and replace it with an identical one. I have boxes full of new-old-stock switches but nothing (of course) with the same dimensions and pinout as the one I removed, so I hit the usual electronics suppliers to see what they had. Anyone who has used those websites knows it can be tricky to find what we want among the gazillions of possible options. The use of specific search parameters is essential, but it can still take time to wade through the results. I eventually found one identical in every 88 Silicon Chip respect. While not expensive, there was a minimum order amount, so I usually try to find some small hand tools to top up the order amount. It’s a tough job, but someone has to do it! The switch arrived a few days later, and fitting it was much easier than removing the old one! I temporarily reassembled the board and battery holder on the bench and powered it up. I’d like to report that I had fixed the problem, but I’d be lying. It did precisely the same thing as before. Oh well; that wasn’t the first time I’d been well wide of the mark. On to plan B, then. The SD card slot is the only other part that gets accessed from the outside of the case, besides the battery holder and on/off switch. While modern versions of these cameras use MicroSD cards (which can be found up to 2TB [yes, that’s 2000GB] these days!), older cameras like this one utilise the older and considerably physically-bigger SD cards. They are still viable; many laptops come with card readers that can accept this type of media. The customer had a 16GB card in this one and swapped it out with another identical card when he went to service the camera every week or so. That meant the cards got a fair bit of use, as did the card socket inside the camera. I tried using one of my own cards. While most cameras can accept Windows/FAT32-formatted cards, for whatever reason, they typically recommend that any ‘new’ card be formatted by the camera itself. As I couldn’t get to the display, I couldn’t format it, and as his card worked fine via a card-reader on my workshop computer, I made the educated guess that it was likely OK. The user manual states that if a card is faulty, everything will power on, but a ‘card error’ message is displayed. Australia's electronics magazine Doing some micro-surgery Taking all that into account, I turned my attention to the socket itself. As I mentioned earlier, the camera’s interior was pristine, and nothing was floating around inside it, but I put the board under the scope anyway for a look. The soldering was not bad siliconchip.com.au overall, but a few spots looked dodgy up close. A quick going over soon had those looking better. I paid particular attention around the SD socket, as several of the pins looked a bit light on solder as well. And if I flexed the socket slightly, one pin, in particular, appeared to be lifting away from the solder pad. It was difficult to see, even with the microscope, but I decided to re-do the whole row of solder joints as a precaution. Pushing the media in and taking it out puts a fair amount of stress on those joints and, unlike the switch body, the flimsy metal frame of this connector was not well-­ soldered to the board, with just a couple of tiny tabs on either side of the socket near the pins anchoring it down. Many SD connectors are (by design) very lightweight and made to fit in very tight places. Given that one has to ‘push to click’ the media in, then push again to remove it, it stands to reason that some wear and tear is inevitable. I gave each pad a decent sweat of flux and solder, and it looked much better. I couldn’t see anything else evident on the PCB, so this was as far as I would go with it. I reassembled it properly; if it didn’t work now, at least it would be in one piece for the customer. Getting the battery holder back in was a bit of an act, but it was straightforward enough. I loaded up the batteries and hit the switch to ‘Test’. Imagine my surprise when the display lit up straight away! I could surf for files on the media, and I could now adjust settings and do a walk test, noting the blue LED indicating the PIRs detecting my presence. I set the switch to ‘On’ and, after the ‘get away’ period, did several walk-pasts. I’m not much of a runway fashion model, but it did result in photos of me appearing on the card, so I was happy with that. It’s always worth giving a repair a go; after all, it just might work! Return of the dilapidated gear B. P., of Dundathu, Qld is at it again, fixing up someone else’s discarded gear and getting it to work again. It’s certainly cheaper than buying brand new... I bought a pair of touch lights at the local tip shop, assuming they wouldn’t be working. The lights are ‘antique style’ and were in reasonably good condition, apart from some corrosion from age and some of the parts in the shades being loose. So they had nothing major wrong, appearance-wise. After bringing them home, I removed the shades, put 3W LED globes in them, plugged one in and touched it. Nothing happened, so I tried the second one, and it also did not work. I guess this is why the previous owner had discarded the lights. I took the base plates off both lights and opened the black boxes that house the electronics. The first thing I noticed was that both lights had two bad electrolytic capacitors on the circuit boards. I found equivalents in my salvaged capacitors collection. After that, one light stayed on all the time while the other light only worked sometimes, after multiple touches. So there was something else wrong. I could see that these lights used a BT136-600 Triac and a TT6061 IC. I thought I would swap over the Triacs between the two lights to see what would happen. Now neither light worked, indicating that both components were faulty in both lights. This was likely caused by the bad electrolytic capacitors. As I did not have either component in stock, I ordered them on eBay. They weren’t available from Australian sellers, so I had to order both parts from China. Once they arrived, I fitted them and set the lights up for testing again. Now both lights worked. However, one feature of the lights did not work correctly with the LED globes. The first touch is supposed to turn the light on to a dull setting, but they were obviously designed for incandescents and the LED globes flicker badly. Touching the light a second time changes it to bright mode, and the LED globes no longer flicker. Touching the light again returns the light to dull mode, but there is now very little flickering. Another touch turns the light off. So the lights were now working correctly, other than the problem with using LED globes. The best solution is just to touch the lamp twice to turn it to bright mode straight away. There isn’t much difference in brightness with the LED globes between the two settings anyway. I was able to screw the bases back onto the lights after finally completing the repairs. After that, I gave them a good wipe down with a damp cloth. Because the lights are made from brass-plated steel, the surface cannot be cleaned too aggressively; otherwise, it will be further damaged. The slightly deteriorated look of the lights adds to the antique appearance. Even though they are modern lights, they look a lot older than they are, both with the style and the ‘aged patina’. Upon opening the base of the touch lights two bad electrolytic capacitors were immediately noticeable. siliconchip.com.au Australia's electronics magazine July 2022  89 Turning my attention to the shades, I straightened the bent parts on the brackets, tightened the screws and cleaned them with a damp cloth. The shades were actually in quite good condition with all the parts being present and nothing broken or chipped. Then I refitted the shades and screwed the decorative nut on firmly. So for a few dollars for the lights and around $7 in parts (I bought 10 of each component), I now have two working touch lights. So that’s about $5 each in total. I looked online to see if I could find the same light, and I found a similar lamp for $220 for just one! It’s handy to be able to fix things that someone else has thrown away. The fact that these items can be purchased cheaply at the tip shop means that they can be recycled or repaired. Not to mention the massive saving compared to buying new lights. The fault whisperer J. W., of Hillarys, WA ran into that strange situation where he managed to fix a faulty device but isn’t really sure how he did it. Oh well, a win is a win... I was talking to a friend who worked as an audio specialist (now retired) at a Perth radio station about all the equipment he used to work with. He mentioned that he had a Studer A730 Professional CD player that had not worked for a couple of years and asked if I could try to get it going again. I told him I would take a look at it, so it ended up in my workshop with the complete service manual. Upon powering it up, there were no signs of life on the front panel and a strange clicking noise emanating from within. It seemed like a power supply problem to me. I removed the six screws holding the front panel, although one was difficult and had to be drilled out. I was then presented with the main board with approximately 60 ICs, including two microprocessors. With the front panel moved out of the way, I could hear that the noise was not coming from the CD mechanism but seemed to be a relay trying to operate at the rear of the main board. I checked the service manual and found there should be four power supply rails: +5V, -5V, +12V and -15V. The latter three were produced using LM317 and LM337 linear regulators and tested OK. An L296 switching regulator generated the +5V supply, but the output only measured about 0.4V. I downloaded the data sheet for the L296 and found that the current was set to be limited to about 4A. With my CRO connected to the +5V line, I found that it was trying to start but being shut down by its over-current protection. I disconnected the front panel and audio output boards but found the +5V was still not present. I then removed the main board from the case and made a cable for the secondary of the power transformer, so that An exterior (left) and interior (right) shot of the Studer A730 CD player. 90 Silicon Chip Australia's electronics magazine siliconchip.com.au I could run it away from the case where the mains transformer was situated. Now I could move the board around and give it a good visual inspection; nothing seemed to be getting hot or looked damaged. I manipulated the board and then tapped around with a probe, producing no change in the situation. I decided to start trying to isolate sections of the main board and see if the +5V would come to life. After cutting several tracks to no avail, I discovered that the board was multi-layered with a least one copper plane not accessible, so I could not isolate any more sections. I decided to remove the output inductor from the switching regulator and use my high-current linear power supply to replace the +5V supply. This way, I might be able to produce some evidence of overheating from the faulty component. I set my supply to 5V and 4A and powered up the player and my supply. The current hit its limit at the 4A setting, delivering about 2.5V. I then started to feel each component to see if it was getting hot. While doing that, its output voltage increased to 4.1V, with the current still at 4A. A short time later, I noticed that the voltage had gone up to 5V and the current had dropped to 900mA, so the overload had cleared. I then tried to bring the fault back by tapping each component and flexing the board, but it did not fail again. Had the problem disappeared entirely, or was it intermittent? I reconnected the original power and was greeted with a steady 5.1V. After connecting the front panel and audio boards back up, I powered the player up again and was greeted with NO DISC showing on the front panel display. I inserted a CD and pressed play; the player was now working properly. I let it run for a few days before ringing my friend to tell him the news. Two days later, I walked into the workshop to find smoke streaming from the back of the player, although the CD was still playing. I turned it off and lifted the front panel to find the mains filter and switch assembly was quite hot, but the mains transformer was not. I removed the mains filter and noticed some smelly liquid coming from the power switch. It looked like the mains suppression circuit had failed. I ordered a replacement unit and connected the mains transformer to a spare power cord so I could let the system run again. The player ran flawlessly until the replacement mains filter arrived. I fitted that and screwed the front panel back in place. After letting it run for another few days, I rang my friend. He was delighted and told me he thought the player was still worth a few thousand dollars. I saw one on eBay for €3000 – over $4000! It has been a few months now, and the player is still working fine. I never found out what had caused the +5V line to be overloaded. Perhaps it was some sort of ‘tin whisker’ that burned away when I applied 4A continuously. Follow-up to the Clenergy 1.5kW solar inverter R. S., of Figtree Pocket, Qld has a follow-up to the Clenergy 1.5kW solar inverter repair storage that we published on page 101 of the May 2021 issue (siliconchip.au/Article/ 14862)... The “Ground I Fault” message is caused by drift in the Hall Effect based current sensor, which monitors any current difference (caused by faulty panel insulation) between siliconchip.com.au Australia's electronics magazine July 2022  91 The exterior and interior of the motor controller are shown above, while the underside of the replacement motor controller is shown below. It worked fine for a few weeks, but then blew up, fusing one of the tracks (marked in red). the inverter AC output Active and Neutral lines. The sensor is in the bottom-left corner of the inverter and looks like a toroid. There is more than one version of this sensor. The later versions are more stable, so the newer inverters do not have this fault. There does not seem to be an easy way to adjust for the drift. It might be that the only way to fix an inverter giving this message is to replace that sensor with the latest version. Repairing a lathe’s motor speed controller While repairing a motor speed controller, D. S., of Maryborough, Qld discovered a horribly flawed design. Had the controller not failed, it might have been a lethal hazard... B. P.’s repair in the November 2021 Serviceman’s Log column reminded me of a service call I made to a local woodcarver. He called me and said that his wood lathe had gone bang. Being a mains-powered lathe, I advised him to switch off the power and wait for me to get there. When I checked out the lathe, nothing seemed amiss – no damaged wiring, no burn marks on the motors or any other signs of a problem. I switched the power back on and re-checked the lathe. The spindle motor worked correctly, as did the speed controller for it. However, this lathe has a small secondary motor. It is much smaller than the main spindle motor and has a small drill chuck fitted to the end. This auxiliary motor can be used to carve various patterns into the spinning workpiece by adjusting speeds and the cutting bit. This motor did not work at all. There were no voltages present anywhere. I had to remove the top shield over the main motor controls to access the smaller motor controls. This smaller motor is an add-on and was modified to fit the existing lathe. But it seems that its speed controller decided to die a couple of weeks earlier, after giving several years loyal service. The owner decided that he would find a replacement controller on eBay. He did find one and at a fraction of the cost of the original. As the replacement unit had the same connections as the previous one, he fitted himself. It 92 Silicon Chip worked fine for a couple of weeks, then boom! This damage was actually a godsend. As you can see from the photo of the underside, one of the mains tracks intersects a mounting hole that has a metal screw going through it and the metal shield around the whole thing. The separation is so minimal that the vibration of normal work eventually caused the track to short against the shield, causing the track to vaporise. Neither of the onboard fuses blew, and the safety switch for the workshop did not trip off. I checked the Earth circuit from the lathe to the power board and found it safe, and a quick safety switch check revealed a normal trip current of 30mA. So at least the proximity of that track to the shield would not have caused the frame of the lathe to become live, although I don’t know why the safety switch did not trip. I replaced this unsafe device with a new controller made in Australia. Although a bit more expensive, it is a lot safer. Please be very careful buying mains-powered items from eBay. Cheap units are flooding the market, and a considerable number of them are simply not safe! If you have any SC doubts, please consult a licensed electrician. Australia's electronics magazine siliconchip.com.au