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SERVICEMAN'S LOG Two crook MacBook Pro laptops A failing battery pack is a fact of life for laptops once they’re more than a few years old. Most aging batteries simply fail to hold a charge but some can fail catastrophically and damage the laptop’s case in the process. A few weeks ago, a long-standing customer called to ask if I would have a look at a couple of malfunctioning Apple Mac laptops belonging to his daughters. While he knows I focus mainly on Windows-based computers, he was enquiring on the off-chance that I might at least give them a quick once-over and perhaps even get them working again. As this chap is a loyal customer of mine, I couldn’t really say no and one of his daughters duly brought the two computers in to the workshop. Both were Apple MacBook Pro laptops and one of them looked as if it had been run over. I immediately assumed (even though I know assuming makes an “ass” out of “u” and “me”), that it had been dropped and I opened the conversation with that observation. The young lady, who was the worried owner of the bent MacBook, was adamant it hadn’t suffered any such event. This puzzled me, so I asked for more information. She told me that she was working with it the day before and it had just stopped working by turning itself off. She had managed to get it going again but when it booted, an error dialog popped up stating 58  Silicon Chip that the date and time were incorrect. It then died again but not before she’d observed that it hadn’t automatically logged onto their WiFi network, which it usually did on start-up. After that, she couldn’t get it going again and thinking that the battery might be flat, she put it on charge and went out to do some chores. When she returned just a couple of hours later, the laptop’s case was twisted and distorted and the touchpad assembly was protruding from its enclosure, as if it had been punched out from the inside. The other machine belonged to her sister and it too had ceased working properly, though this one had the infamous Mac grey screen of death, indicating an issue with either the operating system or the hard drive. The two machines were identical devices around four or five years old and apart from the obvious damage to one machine, both appeared to have been very well looked after. By now, I was keen to find out what had happened to them, especially the damaged one. That one had really piqued my interest. One of my initial thoughts was some kind of paranormal event. OK, I’m just kidding but it did fit – a laptop goes from happily working to physically ruined within a matter of hours, without anyone so much as touching it. And there’s even a teenager or two in the house to act as a “focus” so what else could it be? Of course, in the real world there’s a rational explanation for everything and I’ll wager that many readers have already guessed what had happened here. I’d heard of it many times in the past but had never previously encountered an actual “live” case in the Dave Thompson* Items Covered This Month • Battery problems in a MacBook Pro laptop • • • Vintage AWA B&W TV set Denon twin-drawer CD player Fan cooling for a Sony LCD TV *Dave Thompson runs PC Anytime in Christchurch, NZ. Website: www.pcanytime.co.nz Email: dave<at>pcanytime.co.nz workshop. And that’s surprising, given the number of years I’ve been doing this stuff. As with all Macs, the internal circuitry is accessed by first removing the plate aluminium back (or base). True to form, there were a dozen tiny (but different-sized) screws holding the base on and one has to take note of their positions and be careful not to swap them around during re-assembly. Unfortunately, because the base on this laptop was twisted and seriously puffed up, removing the screws was an act in itself. I had assumed that as soon as the tension on the screws caused by the warped case overcame the strength of the remaining threads holding the screws in, everything would let go and the threads would be stripped or otherwise damaged. So, to counter-act this force (and prevent further damage), I maintained a lot of downwards pressure on the screws with the driver until I felt them clear the threads. Only then was the case allowed to slowly pop open. However, after the first couple of screws had been removed this way, instead of the pressure decreasing, the warped back was putting even more tension on the remaining screws. As a result, I now used elephant tape (I’m assured no elephants were harmed in the making of this tape) to bind the case together and take the tension while I removed the remaining screws, adding a strip of tape as each screw came out. With the back off, it was patently siliconchip.com.au obvious what had happened; the battery, which takes up almost the entire bottom third of the area inside of the case, had become seriously distended. In fact, the plastic case that usually held the individual cells together had completely ripped open, with a couple of the cells inside the opened package looking like small pillows. These two cells are usually about 4mm thick; now they measured 40mm! They were at the centre of the 6-cell package and it appeared that they were the only ones that had failed in this manner and had caused all the internal pressure. The chassis of this laptop is made from cast aluminium, while the case components are sheet aluminium and plastics. When these are sandwiched and screwed together, the result is a very strong unit but when the cells began expanding, they had nowhere else to go but outwards. Basically, they took the path of least resistance, which explains the distorted chassis and pillowed bottom. Furthermore, because the touchpad assembly sat immediately above the battery, when the cells beneath swelled, the touchpad simply popped straight up and out through the hole it usually sits in. Battery mounting The plastic frame of the battery locates into the chassis with embedded tabs along one side, while three screws on the other side secure it in place. A sticker warns users not to remove the battery, something a bit tough to comply with in this case! Since the battery’s plastic enclosure had no chance of containing the innards when they “went off”, it simply snapped apart at the weakest points. The mounting lugs had broken off from the case and were all still held fast to the chassis, left behind when the rest of the plastic case went west. To make matters just that bit more complicated, the screws were those annoying antitamper types that many manufacturers love so much. If you want to work on Apple products, then you’d better have a good set of specialised screwdrivers. That’s because Apple uses lots of different antitamper “security” screw types. In this instance, the screws holding the back on (and those used in other locations inside the device) are tiny and appear to be a type of Frearson-head screw, siliconchip.com.au similar to a very narrow Phillips style head. A small Phillips driver can usually remove them without making too much of a mess of the screw. By contrast, the anti-tamper screws used to hold the battery in are a variation of the Tri-wing type, called a Y1. I’ve seen cases where people have mangled Tri-wing screws by using non-Tri-Wing bits to get them out, so it’s obviously better to use the correct bit, especially if they are in as tightly as these ones were. It amazes me that they deemed it necessary to hold the battery in with this type of fastener but that’s Apple for you. As an aside, sets of security drivers are inexpensive from the likes of Ali­ Express and are a valuable addition to any serviceman’s toolbox. It really is staggering to think of the number of anti-tamper screws one comes across during servicing. I’ve seen them used in all sort of products, including Bluray players, kettles, mobile phones and garden blowers; in short, anywhere the manufacturer doesn’t want Joe Lunchbox messing around with their products. Of course, determined DIYers won’t let anti-tamper screws stop them from getting in and I’ve even seen cases where bloody-minded individuals have opted to physically break the case open rather than kowtow to these manufacturer-imposed restrictions. Either that, or they’ve completely mangled the screws while attempting to extract them. In the past, I’ll admit to having “seen the red mist” where such screws are concerned, because not having the correct bit to remove them really kills the natural flow of working on a job. The silly part is that I can always jump in the van and go and get a suitable bit. They are usually readily available, which defeats the purpose of using anti-tamper screws in the first place. OK, back to the chase. Once the battery was out of the machine and stored safely outside, I began checking out the collateral damage. Fortunately, the thin aluminium back cov- These photos show the battery as it appeared inside the case (top) and after it had been removed from the case. It had swelled enough to distort the chassis and the back. er was easily coaxed back into shape with some careful manual tweaking and though the metal had stretched a little, it would sit flat enough once all the screws were back in. More worrying was the cast aluminium chassis. I assume that it’s cast and then machined to add threaded holes and other anchor points. Of course, it could also have been C&C machined from a single billet of aluminium (I wouldn’t put it past Apple) but I think that casting is more likely. There’s no doubt the manufacturers make a beautiful job of making components for these machines and of course, this is one of the alluring features of Apple products. The downside is that it makes them expensive to repair if any spare parts are required. To straighten out the warped chassis, someone would have to have the gear to remove the lateral twists and then the skills and tools to panel-beat things back into shape. However, no matter how good someone was at this, any repair would still be 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. December 2016  59 Serr v ice Se ceman’s man’s Log – continued obvious (and it would be expensive), making replacement of the chassis the only feasible repair option. Touchpad repair Repairing the touchpad was fiddly but successful. The assembly is selfcontained and is mounted into the chassis using an aluminium locating tab on one side and two wafer-thin spring-steel strips on the opposite side, to provide a “button” feel for the device. A microswitch is mounted at the bottom centre of the touchpad and spring tension keeps the pad raised until someone presses on it to activate the button (Macs use a single-click system so there are no complicated twin-button assemblies to worry about). The expanding battery had forced the touchpad assembly out of its chassis aperture, easily overcoming the resistance of the two thin steel hinges (or strips) which had partly folded back on themselves as the pad was ejected. These steel strips were each removed by undoing two extremely small screws and the spring steel then gently pushed back into shape. Fortunately, no hard bends had been made in them. If there had been, they would have simply broken when straightened. Once the spring strips had been reformed, they were refitted and the touchpad screwed back into place again. Some minor fettling then saw it operating properly again. Buying spare parts from the local 60  Silicon Chip Apple agents is expensive and there is no need to do so. All the Mac parts one could ever want are available from our eastern friends via the Internet. As an example, a battery (an original Apple part) from a Chinese vendor cost me US$80 including shipping, roughly one-third the cost for the same part here. The chassis was a bit more expensive but still remarkably cheap compared to one from the local supplier. Fortunately, nothing else was amiss and once these items had later been replaced, the owner was back “Instagramming” and “Facebooking” to her heart’s consent. It really was just a matter of fitting the parts and making sure that all the different screws went back in the right place. Fortunately, a screw map is available from Apple to help with this. Fixing the second machine The second MacBook Pro machine was a bit more interesting but I’m not going to relate the boring resolution of the grey screen issue. The relevant thing here is that I initially decided to swap in the hard drive from the first machine (ie, the one with the battery problem). That way, I could quickly get this second machine going again. I could then replace the hard drive and the parts in the first machine when they arrived from overseas. Anyway, I swapped the drive in and fired up this second machine with the back still off, to make sure it worked. It booted OK but the battery indicator showed only 10% remaining. Fortunately, the owners had supplied one of their chargers, so I plugged it in and went about my work. My intentions were that once it had charged and was operating properly, the client could come and grab that one. Unfortunately, it didn’t quite work out that way. I was sitting at my desk doing some important YouTube research when I suddenly heard an almighty CRACK! It sounded as if a machine had fallen from the bench and smashed the LCD panel but an anxious glance towards the direction of the noise soon revealed that it was still in place. Mind you, that’s difficult to tell at the moment as my workshop looks like a bomb has gone off in it. That’s because I’m in the process of renovating my garage/workshops while I’m trying to run the business. Normally, I’m very neat and tidy. On closer inspection, the charging MacBook was sitting at a funny angle and when I turned it over, I could see why. Its battery had just blown out its last set of cells and the cracking noise had been the battery’s plastic frame giving way, similar to the first machine. After a quick underwear check, I whipped the charging lead off and removed the battery, before placing it outside with the other one. I immediately suspected the charger but a call to the client quickly revealed that this wasn’t the charger used with the first MacBook. What’s more, a check with my multimeter indicated that the output voltage from the charger was spot on. So it looked like the charger was in the clear. I began to smell a rat with the batteries. Fortunately, this laptop hadn’t been damaged as badly as the first because with the back off, the “exploding” battery had somewhere to go. The touchpad still suffered but the chassis wasn’t as warped as the first one. I repaired the touchpad and got every­thing ready for when the spares finally arrived. It was all rather frustrating though, because it meant that neither machine could be repaired until the spare parts arrived. A week later, while I still had those two MacBooks in the workshop, I got a call from a new client. She told me that she had just fired up her MacBook and it had given her a time and date warning and wouldn’t connect to the WiFi. My alarm bells immediately rang siliconchip.com.au Vintage AWA B&W TV set Vintage B&W TV sets and AM valve radios can be quite collectible these days. K. W. of Riverstone, NSW recently got two such sets going again . . . I recently had to help a friend whose brother had died and who had kept all sorts of junk, including lots of TVs. In one room, there was an old 1970s Rank Arena colour TV that had a VHF turret tuner (no UHF). Normally, these are reasonably collectible but in this case the woodgrain vinyl had faded to white after some 40 years of exposure to an un-curtained window. However, I wasn’t really interested in the old Rank Arena. Instead, I was interested in what was sitting on top of it – an AWA P1 portable B&W TV dating from around 1965. These are now very collectible and many still give a first-class picture despite their age, often with the original AWV valves. The P1 was an all-valve portable and was basically a full-size TV chassis crammed into a portable cabinet. Thanks to the full-power 6.3V heaters they used, their picture tubes lasted the distance, unlike the ones used in the all-transistor portables that came later. Jim said I could have it as it was no good since the analog broadcasts had stopped and anyway, it had “no horizontal hold”. Across four decades, I and I advised her not to charge it but to give it to me (or someone else) so that the battery could be checked. When she brought it around, a quick check of the back panel confirmed that it too had a swollen battery. It was enough of a coincidence for me to send a warning to my email database, recommending that owners of three to 5-year-old MacBook Pro laptops have the batteries checked out. It might just save them a lot of grief. Denon twin-drawer CD player DVD/CD players are dirt cheap these days so why bother fixing them? R. W. of Lismore, NSW didn’t want to part with his Denon twin-drawer CD player so when it began playing up, he rose to the challenge and fixed it. Here’s what happened . . . siliconchip.com.au remembered that the most common fault in the P1 was a leaky 0.0068µF paper capacitor in the vertical oscillator circuit. I also knew that people invariably confused loss of vertical hold with lack of “horizontal hold”. Back home, I put it on my workbench and applied power. I could see that the valves were lighting up but there were no other signs of life, which usually meant that the HT fuse had blown. This is a common occurrence if such sets haven’t been run for a few years and usually occurs because the power supply electrolytics need re-forming. The usual cure is to connect an ammeter across the fuseholder and then carefully bring up the mains voltage from zero with a Variac, while monitoring the current until it stabilises. Sure enough, after half an hour or so, everything began to work and I was rewarded with a crisp snowy screen and a healthy hiss from the speaker. I hooked up my old TV pattern generator and yep, the vertical hold was way off and there was the dodgy 0.0068µF “Hi Qual” capacitor exactly where I remembered it (“Hi Quals” were basically a paper capacitor with a plastic case!). I replaced this capacitor and the old AWA P1 then worked perfectly. I was even able to download a PDF of the complete 1965 model service manual but I didn’t really need it. I I have had a Denon DN2000F MkIII twin CD player for many years. This is a rugged 2RU rack-mounting unit with a separate 2RU controller connected via a proprietary lead. I first obtained this unit in the 1990s after being retrenched from the airline industry and deciding to try my hand at being a DJ. That wasn’t a success but I kept the player as its cueing facility and variable pitch was something I had grown used to. It gave reliable performance until recently, some 25 years after purchase. The problem was that disc drawer one would load a CD but would not cue it. However, assisting the drawer to close or turning the power off and then back on again (doesn’t that “fix” everything these days?) with a disc inside allowed it to cue and play normally. fully expected it to start to play up after a couple of hours but remarkably, apart from dirty tuner contacts and a noisy volume control pot, the capacitor was the only real fault! I then wired up the luminance output from a digital set-top box (STB) to the grid of the video amplifier valve and got a really good picture. The sound was just as easy; I simply wired the left and right audio channels from the STB in parallel to the volume pot. The next time I went down to Jim’s place I said, “Good news! I got your old black and white TV running”. He was unimpressed because, as he said, “you’ll still need a set-top box”. While I was there, Jim brought out his 1940s-era Mullard 5-valve radio. It was faulty and he wanted me to have a look at it. Back home, I quickly discovered that it required two new 22µF 450V electrolytic capacitors and a few other minor parts to restore it to full working order. Interestingly, a note had been attached to the back, detailing how the set had been repaired by a service centre back in 1986 – which would have been a bit of an ask even then. Oddly, they had changed quite a few capacitors but not the one you must always change: the grid coupler from the plate of the audio preamp to the grid of the output valve. It was still there when I got the set and leaking like the proverbial sieve! When listening to the drawer operate, it was obvious that the transport motor was running for a short time after the drawer either closed or opened, so I suspected that the limit switches either weren’t being actuated or had developed a fault. Fixing it wasn’t urgent and so I put up with this minor fault for quite some time, preferring to use drawer two instead. Eventually though, drawer two also started playing up. In this case though, the transport motor was stopping when the drawer reached the open or close limits while being assisted. This was the impetus I needed to take it apart and see what the problem was. After dismantling the unit, which appeared to be well-made, I inspected the PCBs for bulging electrolytics and discoloured components and found December 2016  61 Serr v ice Se ceman’s man’s Log – continued Left: the fault condition was triggered in the LCD panel of the Sony set about 40 minutes after switch-on. Fitting a couple of fans to the rear cover helped cure the problem. Cooling fans were commonly used in the plasma sets of yesteryear but in this instance, retrofitting fans to a 132cm Sony LCD TV saved it from the scrapheap. G. S. of Castle Hill, NSW was the retrofitter . . . The Sony KDL52Z5500 LCD TV was a top-of-the-range model costing over $3000 back in 2009. However, after just five few years of use, the 132cm LCD panel in my set suddenly began giving trouble. Initially, the problem showed up as a narrow vertical flickering band on the lefthand side of the screen at power up. This would then disappear after a few minutes as the set warmed up and so the fault was initially considered trivial. It didn’t stay that way though and over the next few weeks, the switchon fault progressively became more serious. It eventually got to the point where the entire lefthand side of the screen would take on a reddish hue with very dark shading, picture tearing and vertical ghosting. It would then invariably come good and display a perfect picture after 30 or 40 minutes (when the panel had warmed up) until one day it didn’t, despite leaving it running for several hours. This sort of problem is often due to faulty “tab” connections between external flat ribbon cables and the transparent electrodes just inside the edge of the LCD panel. With repeated thermal cycling, the bonding contacts inside the LCD can become intermittent and a panel failure of this sort generally means that the set is a write-off. However, there’s one neat trick you can pull to try to save it: remove the metal frame that runs around the outside of the LCD panel (and secures it in position), run draught excluder around the inside of the frame and reassemble it. The idea here is that the draught excluder applies extra pressure to the tabs when the metal frame is fastened back into place and will hopefully “cure” the problem. This fix initially worked a treat for my Sony set, as detailed in Serviceman’s Log in the November 2014 issue. However, after a few months, the problem reappeared but with one important difference: the timing of its appearance had been “transposed”. Now, instead of the fault occurring when the set was cold, it was appearing about 40 minutes after switch-on, after the panel had thoroughly warmed up. What was frustrating was that the picture was perfect for those first 40 minutes or so. After that, the dark shading, ghosting and reddish hue would suddenly appear and it none. I then removed drawer one and located a small PCB which held the two limit switches and interfaced them to a flat lead with a polarised header. There were no other electronic parts on this board other than the switches. One was a very small unit similar to a microswitch and this was the closelimit switch. By contrast, the openlimit switch consisted of a flimsy pair of contacts in a rubberised cover that was actuated by a slider on the drawer unit (which also contained the end-oftravel buffer springs). Both switches measured greater than 500Ω when closed, so I applied some contact cleaner, reassembled the unit and tested it. That fixed it but the fault was back less than a week later. I tried looking everywhere on the internet for a replacement board or, failing that, replacement switches but to no avail. I then emailed Denon but was told that this player was no longer supported. A supplier in the UK had complete drawer and laser assemblies but at £300 (about $550), that was too much to spend, especially as I needed two. Then I had a brainwave. If I could replace the existing switches with suitable microswitches, I just might be able to resurrect the unit. After a brief search, I found some at Jaycar (Cat. SM1038) and bought four at just $4.95 each to try. After removing the old switch PCB, I actuated the existing switches and checked the resistance. The open-limit switch was now open-circuit but the close-limit switch was OK, although the drawer motor still ran when the drawer was closed. I gave this no further thought and decided to replace both. And that’s where the fun began. The new switches were several times larger than the old ones and it was difficult to determine where to mount them. After much trial and er- Fan-Cooling For A Sony LCD TV 62  Silicon Chip siliconchip.com.au was so bad that the picture was unwatchable. Clearly, the fault was heat-sensitive; the LCD panel had to get nice and warm in order to trigger it. So what could be done about it? The obvious answer was to somehow keep the panel from reaching the critical “trigger” temperature and using computer fans to extract the set’s warm interior air seemed to be the way to go. After some hunting around on the internet, I came across a CoolerMaster 120mm case fan from a local retailer that seemed ideal for the job. It ran at 1200 RPM, had a quoted noise level of just 19.3dBA (so it would be nice and quiet) and came in a dual pack for just $19.00. Mounted together side-by-side, the two fans would be just large enough to cover a large ventilation panel towards the top righthand side of the rear cover. When I got the fans home, the first thing to do was to figure out whether to mount them inside the rear cover or on the outside. After some thought, I decided to mount them on the outside and power them from an external 12V DC plugpack. That way, they wouldn’t block the airflow to the horizontal ventilation slots at the very top of the rear cover. With that decided, I undid the umpteen-dozen screws that secured the rear cover, laid it flat on the floor and used one of the fans as a template to drill two diagonally-opposite mounting holes. This fan was then secured in position using Nylon M4 x 15mm screws, nuts and wash- ers, after which the second fan was mounted in position, butted hard up against the first. Nylon mounting screws were used at all four mounting positions because I didn’t want metal screws protruding into the chassis, with the risk that they might contact a high voltage or short something out. Once the fans were in place, I replaced the rear cover, then sorted through my spare parts and found a 2.5mm DC socket. This was mounted on a small Perspex bracket which in turn was attached to an outside corner mounting hole of one of the fans. The DC socket itself was wired to two paralleled 3-pin polarised pin headers and the two fans then plugged directly into these headers. Several cable ties were then used to tidy up the wiring and secure it all in place. Now for a power supply. A quick ferret around in my workshop soon turned up a 12V DC plugpack supply rated at 600mA – more than enough to power the two 160mA fans. I plugged it in, switched on and the two fans whirred into action. And just as their noise specification indicated, they were nice and quiet – so quiet in fact that you weren’t aware they were running from a normal viewing position. So did the idea work? It sure did – well almost! The set now runs for 3-4 hours before giving trouble, as opposed to the measly 30-40 minutes before the fans were fitted. Running the fans at a higher speed (eg, by increasing the supply voltage by 1-2V) or adding extra fans would probably solve the problem completely. ror, I settled on the two positions and after soldering fly-leads to both, temporarily secured them in place using a dab of contact adhesive. I then operated the drawer manually and the positions seemed correct. It was then that things went pearshaped quickly. To gain access, I had removed the cover to the drawer which held the top-clamp for the disc when the laser is in position. This cover also holds the drawer mechanism in place and while I was testing the switches, the drawer fell out and took one of the sliders with it. I tried to get the mechanism back together but just couldn’t find the right position. I wished then that I had a time-machine to take me back to just before it fell apart. However, perseverance eventually paid off and somehow it all eventually clicked back into place. Operating the drawer now revealed that the drawer rack was not correctly aligned with the drive pinion and wouldn’t run to its full travel. The drive mechanism winds the drawer in and on reaching the inner limit, a mechanical disconnect operates and the drawer motor then drives the laser assembly into position before finally operating Inside or outside siliconchip.com.au Substituting microswitches for the original limit switches and relocating the switch PCB helped get a Denon twin-drawer CD player working again. the close-limit switch. After more fiddling, I finally got it right but don’t ask me how. The next day, I verified the switch operation and applied a 2-part epoxy adhesive to permanently secure the microswitches. The fly leads were then soldered to the switch PCB which was trimmed and encapsulated in clear heatshrink tubing and relocated to the side of the mechanism. It all looked good, so I reassembled the player and put it through its paces. It failed and as can be imagined, I was rather crestfallen. Neither of the switches was being activated. The open-limit one was out by about 1mm but the close-limit switch wasn’t activating at all. The drawer would close but the laser assembly wasn’t lifting into position. So I had another fault that I had failed to notice and that was that the motor didn’t seem to have enough torque to operate the laser lifting mechanism due to a slipping belt. So why hadn’t I noticed the belt? It couldn’t possibly be OK after 25 years and indeed it wasn’t. I went back to the internet to see if I could find spares and eventually came across a supplier in Portugal from whom I bought two generic 25mm diameter 1.2mm belts for under $10, including postage. These were installed and after a slight adjustment to the open-limit switch actuator, the player was reassembled and tested. That was it – both drawers now worked faultlessly, although drawer two may also need to have its limit switches replaced sometime in the future. And so, for an outlay of less than $30, the old Denon DN2000F CD player was given a new lease of life and may well last another 25 years. Will CDs still be around in 2041 and if they are, will SC I still be around to use them? December 2016  63