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SERVICEMAN'S LOG Video trials and tribulations Dave Thompson* What did we do before USB flash drives became available. They certainly simplify the playback of digital content but even though they are not mechanical, I have found some unexpected reliability problems. We have become so used to the innate reliability of electronics equipment and it now it seem that can no longer be taken for granted. Still, if you are prepared to delve into these problems, the repairs can be quite simple. Long-time readers of this column may recall the trials and tribulations I experienced when we purchased a new home-theatre system a few years back. My main gripe was with disc region codes; after years of playing discs from all regions in our old, all-zones player, this new Blu-ray capable system would only play Zone 4 discs. For those unfamiliar, powerful entertainment-industry lobbyists forced major manufacturers to implement a region coding system for DVDs, which meant, for example, discs produced for the American market wouldn’t play on a system designed for the Australasian market. This was apparently done to protect the industry from loss of income due to them not having control of when and where movies are released. But what it really does is impose price-fixing and monopolising practices onto consumers, which is why there is barely any legal basis for disc zoning in most countries. Thankfully, some manufacturers ignored these directives and consequently most of us had relatively easy access to region-free DVD players, at least we did until Blu-ray came along. Once again, consumers on this side of the world are forced to buy inflatedpriced discs long after northern-hemisphere buyers get to enjoy them, while they also have a larger variety of titles at subsidisedby-us prices. Some good news is that there is a huge, quasi-underground network of dedicated reverse-engineer types working to provide region-free firmware for all brands of consumer disc players. Except that back then, there was no firmware available for our particular player, and while there might be something now, we’ve long-since worked around the issue. For starters, we don’t play Blu-ray discs, and most of the material we watch is digital content stored on USB media, so it isn’t such a big deal any more. The biggest blow back then was the fact we couldn’t play any of the dozens of European (Zone 2) discs we’d picked up on our travels, including many titles that were never released on DVD in this region. How these corporate bullies still get away with dictating what we can watch and when (if at all) escapes me, which is why I enjoy undermining their efforts to beat me down. Note that I’m not advocating ripping off studios or creators, I’m talking only about legally-acquired media. When I discovered this LG system was region-locked, I very nearly returned it and likely would have, until I learned there were no region-free Blu-ray home-theatre systems on the market here yet to swap it with. Such is technological progress. USB is the answer This means the main way we watch content on our system these days is via a USB flash drive. The system is network capable, and “internet ready” but the proprietary WiFi dongle it requires is so ridiculously overpriced I refuse to buy it. Running a permanent cable is not feasible either, given the location of 60 Silicon Chip Celebrating 30 Years siliconchip.com.au Items Covered This Month • • • Blu-ray player and HandyCam 360° passive infrared sensor repair Fuse blows, stove goes *Dave Thompson runs PC Anytime in Christchurch, NZ. Website: www.pcanytime.co.nz Email: dave<at>pcanytime.co.nz the system and the distance from the nearest network switch. It’s not really a bother; we simply load up what we want to watch on a flash drive and put it into the single USB port in the front of the player; after a few seconds we have a basic file-system we can surf around using the remote and choose the file to play. However, of late, we’ve had a few problems with the drives. Initially, I thought we might have worn out one of them, as it would "drop out" once or twice and we’d have to re-insert it and fiddle about to try and find where we left off. This was annoying but with it only happening every now and then, not a show-stopper. Eventually I bought a couple of higher-capacity flash drives and was mildly peeved to find one sporadically not being recognised by the system. Eventually, it got to the point where none of the drives would register until we plugged and re-plugged the drive and even then only with significant wiggling around; siliconchip.com.au obviously there was something amiss. Like all servicemen, I’m always ready to drop everything and head to the workshop. This particular night we were hyped to watch a particularly good show and the air was rendered blue when we discovered that none of the flash drives would "play". After unplugging the raft of cables and plugs connecting the base unit to the speakers and peripherals, I repaired to the workshop to do some, er, repairs. Opening the thing up was simplicity itself. Six small screws held the metal "top-hat" style metal case onto the base. The shape of the cover required me to splay the bottom edges out to lift it straight up and away to reveal the interior. The USB socket was in plain sight, though due to the way it was situated, the soldered connections were underneath the board. So another half a dozen screws needed to be removed and a few flying leads and plugs removed before I could flip the PCB over. Immediately I could see the problem: every one of the socket’s four solder joints had a tell-tale dark ring around the lead coming through the board. Flexing the socket widened these rings on one side and compressed them on the other, indicating that all were fractured and would only electrically connect when the socket was pressured this way or that. No wonder the programs were dropping out and it was hard to get the drive initialised in the first place. In fact, I was surprised it worked at all, given the gaps in the solder joints. By this time my soldering station was well up to temp and a quick application of heat and a press of the button on my Goot solder sucker soon had each pad on the PCB and the socket’s leads clear of old, dry solder. I sweated in each joint with a fresh pool of solder and flipped the board over to check it had gotten Celebrating 30 Years right through to the opposite side as well. It all looked good and within 10 minutes the screws were back in and I was in the lounge plugging all those cables back in. From that point to this, any flash drive inserted registers almost instantly and is ready to go within seconds. Interestingly, I never recalled it being that good before, so perhaps it had been defective right from the word go. There was certainly very little solder on those connections and a lot less that it has now. I guess this is the price we pay for lower-cost electronics in general but surely a bit more solder all-‘round wouldn’t break the bank. HandyCam challenge Another challenge I faced recently was with my Sony HandyCam. While this is now about 10 years old, it is still a pretty good little camera and since I need a decent camera for my new YouTube venture, it was, as the Americans say, a "no-brainer" to dust it off and charge it up, ready for testing. Over the years, I’ve taken a lot of video and stills with this camera. The 4-megapixel sensor might be a bit lame compared to what’s available now but back then it was the business. However, since in all those years I’d never dumped many of the photos or videos I’d taken from the 40-gigabyte hard disc, it was pretty full. I recently recorded a couple of test clips with it and while only HD rated (720p), it will do me fine, until I can afford to shell out for a mirrorless, DSLR FHD camera that can do 1080p at 60 frames a second. Best tools for the job, right? And therein lies my problem; the display shows a mere 18 minutes of hard-disc space remaining if I continued filming at the current resolution. To do anything serious, I’d need to December 2017  61 dump the data on the camera’s drive to one of my computers to free up a bit of space. To accomplish this, Sony deemed it necessary to provide just one way of getting the files from the camera to a computer. Actually, there were two, possibly three ways, but I’ll talk about that in a minute. The problem was that in the shift to this new house, I’ve misplaced the supplied USB docking station the camera requires for a computer connection. A quick look on the local auction sites didn’t show any of the correct model for sale and according to references I found in forum posts regarding the subject, Sony have long-since stopped making and selling them. I also tried the usual Chinese online sources but there was nothing there either. Convinced the docking station must be packed away in one of the dozens of boxes we still hadn’t un-packed, I spent an entire weekend opening and sorting through so much extraneous rubbish that I was almost ready to dump it all straight into a skip. I don’t consider myself a hoarder and it isn’t like I have to sleep standing up because every square metre of 62 Silicon Chip floor space is packed to the ceiling with swag but I do appear to have a lot of stuff I could well do without. How I ever accumulated it all is a mystery. I can’t recall buying a lot of it but it’s there so I must have acquired it at some stage! Annoyingly, though, the docking station was nowhere to be found. It was time to get creative. I blew the dust off my eBay account and hit the international auction sites to try and find one. The model I was after is the DCRA-171, made especially for my camera and a handful of other models. I found a couple, and was quite excited until I saw they were asking as much as US$95! That seemed a little steep, but I guess the price reflected just how hard to find these things were becoming. After a bit more digging, I found one listed on the UK eBay site, for a much more reasonable £12, roughly NZ$25. I placed a bid after discovering they shipped overseas and even with shipping included, I’d be looking at about fifty bucks, still a bit high but realistically a much more reasonable amount. The day of the auction came and went; when checked I discovered it had been purchased by someone else Celebrating 30 Years after a small bidding war for £35! This was getting tiresome. It was about this time I noticed the camera also has a memory card slot. It is tucked away under the fold-out LCD screen and I’d never really noticed it before. This could be the solution. If I could still get a memory card to fit it, perhaps I could transfer the files from the camera’s hard disc to the flash media and transfer them to the computer using a card reader. That sounded much more feasible. I checked AliExpress and the MSDuo cards the camera took were as cheap as, er, chips and it was no big deal if I had to wait a little while for it. However, before I committed myself, I checked the camera’s user manual and believe it or not, there is no way to transfer files from the hard drive to the memory card. I could do it the other way, from the flash drive to the hard disc, but not the way I needed. Darnit! However, while I was looking on AliExpress, a camera caught my eye; it was one of those "action cameras" with all the cases, mounts and trimmings for just US$45. Cheaper than a docking station and with claims of 4K video at 25 frames per second, this seemed an ideal solution to my problem. The only extra hardware this camera required was a microSD card and as I already had a couple on hand, I wouldn’t need to buy anything else. Sadly, I put the Sony back in the drawer while I waited for this one to arrive. I had plenty else to do in the meantime so I went on with that instead. The camera duly arrived and I was impressed. It came with a clear, water-proof housing and a dozen other adaptors and mounts for helmets, handlebars and tripods. I mounted it onto my tripod and set about testing it out. The first thing I discovered was that when set to 4K recording, it could only manage about one or two frames per second; a long way away from the 25 FPS claimed. No real harm; I wouldn’t record in 4K anyway, so it was moot. However, after further trials, I discovered the camera could only manage a maximum of 23 FPS at 720p and while truthfully I had no right to expect a 4K, 25 FPS capable camera for that money, I still felt burned. And then there is the audio quality; the on-board mic level was poor and while this was to be expected when mounted inside the water-proof case, even when sitting outside the case the siliconchip.com.au audio capture wasn’t great. If I did use the camera, the cover could be handy as at times it would be working in a dusty workshop environment. As a potential workaround, I carefully bored a 2mm hole through the plastic case adjacent to the mic aperture in the camera’s case – after all, it wouldn’t be going under water. While this improved things a bit, it wasn’t enough to allow me to record without an external mic, which the camera doesn’t have facilities for anyway. Boy, this YouTube stuff is difficult! With that camera a dead duck, I returned to the Sony and the web. I eventually stumbled upon a schematic someone had drawn up depicting the DCRA-171 docking station’s proprietary USB connections. This was more like it; this might enable me to solder a cable or connector directly to the camera’s PCB. Though heartened, I was reluctant to pull the camera apart. I remembered last time I repaired it, how complex it was and this time I would need to strip it down even further, right to the bottom of the camera. I took my time and after careful parts removal, finally reached the socket. To my dismay, the connector markings bore no resemblance to the diagram. Nothing tallied and the two components seemed miles apart, with nothing referencing the other. There were no pin numbers visible and though I had a good go with a multimeter, trying to ‘ring out’ the ground, +5V and data + and - leads and match anything at all to the diagram, it was to no avail. Annoyed, I reassembled the camera, wondering where to go from here. Then, I got lucky. As if on cue, an email notification popped up saying a keyword search I’d set up on a local on-line auction site had a hit. I immediately went online found a guy selling a DCRA-171 docking station for $20 plus shipping; I bought it on the spot. It arrived a few days later and I hoped like hell I’d not caused more problems mucking around with the socket. I needn’t have worried. The USB connected straight away and I cleared the files from the drive. Now: lights, camera, action! 360° PIR Sensor Repair When something breaks, usually the worst case is that you have to replace siliconchip.com.au it with a new one. B. P., of Dundathu, Qld did just that, only to find that not only was the brand new unit broken and would need to be fixed, it also had to be modified to fit where the old one had been mounted! Here is the story as he tells it… When we built our new house in the early 1990s, I installed a 360° PIR (passive infrared) sensor underneath the front verandah, near the outside edge, to operate two coach lights on the front wall of the house (either side of the front door) automatically whenever someone approached. The sensor only worked for a short time. I wondered why it had failed when it was still nearly new, so I removed it and inspected it. I found that the circuit consisted of a 270Ω 0.5W resistor in series with an X2 capacitor, followed by a bridge rectifier, zener diode and electrolytic capacitor to supply the low voltage to operate the unit. This is the same arrangement used in many low-power mains-connected devices. It was the inrush current limiting resistor that had burned out. Luckily, the resistor had burned out in such a way that I could still read the value. I replaced the resistor with the same type and as a precaution, I wrote its value on the PCB, just in case it ever needed replacing again. The unit then worked again for a short time, before failing yet again and it was the same resistor that had burned out yet again. I could see that this was going to be an ongoing problem, so I decided to replace the resistor with something more substantial. I looked through my stock and decided to use two 150Ω 1W resistors in series, as that was the closest I could find at short notice. The total was 300Ω, but it should work OK. Well, that was obviously the right thing to do as the unit then worked for over 20 years with no issues, until one day when my wife said that it had stopped again. I took the plastic cover off and it promptly disintegrated in my hand due to its old age. So clearly, I needed to replace the whole thing, no matter what was wrong with it. A couple of days later, we were in Bunnings so I headed to the electrical department and we soon spotted a similar unit on the display wall. However, when we checked the shelf, there were none in stock. In a stroke of luck, the company rep for that brand was in the store doing Celebrating 30 Years December 2017  63 a stock-take, so she grabbed a ladder to scan the unit on the wall to check the stock. On her way up the ladder, she spotted a box at the back of the top shelf, with the last remaining 360° PIR sensor, so we bought it. Later, when I went to fit it, I checked the light switch for the old sensor and it was off, so it's possible that the old sensor was still in working order. The problem had been that a storm one night, some time back, kept tripping the sensor and turning on the coach lights, which are near our bedroom, so it had been turned off and we then forgot to turn it back on later. Note to self: next time, check that the unit is switched on before taking it apart to fix it! Anyway, I got set to fit the new sensor and the first problem was that I needed to drill new holes in the Villaboard ceiling because the new sensor had a different mounting arrangement to the old one. I screwed the base to the ceiling with the idea being that the PIR sensor itself would then clip into the base. But when I grabbed the unit itself, I could see that there was a problem because the three-wire terminal block protruded and would foul the ceiling. That would mean I would have to drill a large clearance hole in the Villaboard, which I did not want to do. I can’t say I was very impressed with the design at that stage. However, I was able to cut the terminal block into three individual terminals with a Stanley Knife so that the terminals could lie flat and therefore fit in the recess in the back of the unit. Problem solved. As I proceeded with the installation, I thought I would set the three adjustments: LUX (light threshold), SENS (movement sensitivity) and TIME (light on-time) to the values I wanted. I set SENS to maximum and LUX to a daylight level so I could test the unit after installation. But when I went to set the time to the minimum, the small adjusting knob kept turning and did not stop. Something was obviously wrong there, so I took the unit down and opened it up. The two sections of the case are held together by four clips around the edge of the unit, so I was able to separate them without too much trouble. A closer look revealed that someone had tried to adjust this unit on a previous occasion and turned the adjuster hard against the stop and broken off the small square plastic extension of the knob that sits inside the pre-set pot. What to do? I could not take the unit back for exchange because it was the only one in stock and besides that, I had already modified the terminal block. There were three choices: bin the unit, put it up with the broken part or try to repair it. I quickly ruled out the first two, so I had to work out a way to repair this small plastic knob. I needed to think of something to add a new square extension to it, in order to restore it. I tried to think of something of the right size with a square cross-section to replace the broken piece of plastic with and then I realised a matchstick would do the job. I cut the head off a match and compared it to the broken piece; it was an almost perfect match. So I removed the knob and very carefully drilled a hole where the stop had broken off, using my cordless drill at minimum speed, while holding the knob in my fingers. I started with a 1/16-inch drill, then a 5/64-inch drill, then a 3/32-inch drill. The resulting hole was a tight fit for the matchstick shaft, so I glued it into the hole using a drop of super glue. I then trimmed the match to length carefully with a fine-tooth hacksaw blade and reassembled the unit. This somewhat unusual repair resulted in the restoration of the sensor to “good as new” condition and saved it from the bin. Unfortunately, these days, things are not made to be repaired, so you often have to be crafty when it comes to repairs. I was then able to adjust the delay time to just above the minimum set- Servicing Stories Wanted Do you have any good servicing stories that you would like to share in The Serviceman column? If so, why not send those stories in to us? 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. 64 Silicon Chip Celebrating 30 Years ting and soon had the unit mounted in place. Job done. I turned the power and light switch back on and went outside. The lights were on, but they stayed on for over a minute, so I started thinking that maybe there was a fault with the unit. Then the lights went out. That was a relief as it just meant that the TIME adjustment was set too high. I set it to the minimum and stepped aside. The lights stayed on for eight seconds, so that was too short. I advanced the setting small amount and this resulted in a 15-second delay before the lights went off. I was aiming for 20 seconds, so I adjusted the setting by a hair and stood aside. The lights then stayed on for well over a minute, which was far too long. I set the adjustment back by a hair and this resulted in a 15-second delay again. This adjustment was far too sensitive, so I just settled for the 15-second delay. I then set the LUX setting to a suitable level for night-only activation and the job was done. Exploding circuit board in my stove! R. B., of Kambah, ACT was cooking a stir fry when his induction cook-top abruptly gave up the ghost. Luckily, the repair was reasonably straightforward and economical, considering the high purchase price of the unit... Recently, I was cooking the evening meal on my Belling stove which has an induction cook-top. About halfway through cooking, the stove went BANG and the cook-top stopped working. I rushed around and found a portable butane cooker to complete the stir-fry. After dinner I searched out the warranty and purchase documents for the stove; it had a 2-year warranty but the purchase was three years ago. Not good. Knowing that the induction cooktop was the most expensive part of the stove, I was thinking this problem was going to be expensive. With this in mind I was keen to investigate the problem and possibly repair it. To this end I began to dismantle the stove. It was not too hard to remove the glass top as a unit, before which I had pulled the fuse on the stove circuit. To remove the top required removing four screws at the back and disconnecting the power supply to the induction top and also unplugging the signal wire connections to each of the siliconchip.com.au control knobs on the front of the stove. Laying the stove-top upside down, I was able to remove the screws around an aluminium tray which held the induction unit under the glass top. Turning the tray over it, was a simple matter to click out the induction coils and unscrew their cable connections to a circuit board. The coils had to be removed to get to the Torx screws which held a plastic tray to the aluminium tray. This tray has three circuit boards clipped into it. Once the plastic tray was free it was a simple matter to clip out the circuit boards after marking and disconnecting the power cables and digital cable connecting to a small control board. Looking for the cause of the BANG, on removing a power filter board I found that underneath was a large black soot and vapourised copper splatter on the board and in the plastic tray. After scrubbing all of the splatter off the board it was clear what had happened. This board had a narrow track, with slots punched each side, designed to be the fuse. To support this analysis, on top of the board paralleling this track is provision to install a proper 240VAC-rated fuse. Therefore to make the repair I installed an appropriately-rated glass mains fuse. There was another similar fuse on the other edge of the board which I also replaced with a glass fuse and then cut the copper track. Having repaired the fuse I had to then determine the reason for the fuse blowing. On the induction heating coil driver board, there is a power transistor and large capacitor for each cook plate. Checking the large transistors with an ohmmeter, I found that one transistor was clearly fused (zero ohms between all leads). On looking at the board markings the three leads on the transistor were marked C, E and G – odd; I have not seen a transistor marked this way. Using a solder sucker I unsoldered this transistor, and to remove its heatsink I was able to use a long clamp to pull the clip sideways to cause it to pop out of the groove; I did not want to deform the spring in the clip so that it could be reused. Once the transistor was out I could read the markings “TOSHIBA 40RR21”. Finding the datasheet on the internet, it is an Insulated Gate Bipolar Transistor (IGBT) and “Dedicated siliconchip.com.au The underside of the stove-stop which shows the various induction coils and their cable connections to the circuit board below. These coils were removed so the aluminium tray could be unseated and the circuit board freed. to Voltage-Resonant Inverter Switching Applications”. The resonant circuit appears to be formed with a large capacitor and the induction coil for each hot plate. Being a specialised device I was not so confident I would be able to find a replacement. However, a Google search found a replacement at www. aliexpress.com My stove cook-top is now working as before, except next time I should not have to clean up all the spatter and a fuse blow-out will be safer. SC One of the power transistors on the induction heating coil driver board had fused and needed to be replaced. Celebrating 30 Years December 2017  65