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SERVICEMAN'S LOG When spare parts aren’t around Some things just aren’t made like they used to be. When tools break you would expect that it would be cheaper for the manufacturer to supply spare parts than expect the consumer to buy a new tool. Some of my earliest and happiest memories are of being in my father’s workshops. I say workshops, because like many engineering types, he had several different shops over the course of his working life. The first I remember was literally on the “other side of the tracks” in an area that was considered a little bit, well, industrial. At that time, Dad was making materials for a fishing rod manufacturer. He’d designed and built a machine – his lifelong specialty – that took multiple threads of glass fibre from huge spools and pulled them through a heated mould. Depending on which mould was being used, either a solid or tubular fiberglass rod magically emerged from the other end. This machine almost certainly dictated the type of workshop required due to its bulk, and was why this particular location worked out so well. He also did a lot of other work from that workshop. For as long as I can remember he was the neighbourhood’s go-to guy for fixing everything from siliconchip.com.au TVs to talking dolls. These were the days, the mid-sixties, when people actually held onto the stuff they had, as opposed to just chucking it away and buying a new one. Mind you, manufacturers back then had a different philosophy as well, to make the best possible product and to make it last, even while making spare parts widely available should the worst happen. It made a lot of sense for owners to repair rather than replace, and while that meant the cost of buying new was dollar for dollar more prohibitive than it is today, products lasted much longer. This all meant that Dad had an almost never-ending stream of jobs across his workbench and it was always littered with a variety of gadgets and the specialised tools he sometimes made to fix them. The nannystate’s health and safety police of today would likely have a fit if they could have seen this workshop, with Dave Thompson* Items Covered This Month • • • • Nail gun – replace or repair? Medion computer Roberts DAB radio Toyota RAV4 speedo fault *Dave Thompson runs PC Anytime in Christchurch, NZ. Website: www.pcanytime.co.nz Email: dave<at>pcanytime.co.nz the holes in the floor, exposed whirring and spinning machinery and the constant smell of hot fibreglass resin but I loved it and recall being very sad when Dad moved on from that venture to something else. Fast-forward ten years, and his workshop was then almost exclusively electronics. This was during the CBradio craze of the mid-seventies and Dad was manufacturing a CB radio called the Telstat Minicom. My interest in electronics was getting more serious and this workshop was like a little slice of heaven for me. Given it was only a few kilometres from home, I ran there every day after school under the guise of “training” for athletics but my motives were ulterior. I would spend an hour or so with Dad and his then business January 2017 43 Serr v ice Se ceman’s man’s Log – continued partner, sometimes helping stuffing circuit boards, punching holes in chassis or simply watching and learning. Sadly, once the CB fad wound down, so did that business and Dad moved on to a home-based business, which meant his home workshop, which was already quite well appointed, gained some new specialised machinery and tools such as rotational moulders and vacuum formers. Eventually, I picked up that mantle of the local repair guy and I’m still asked to repair home stereos or old radios and the like, mainly because the particular device holds sentimental value. However, dare I say it, I think the art of repair is disappearing, thanks to this replacement culture, and manufacturers have a lot to do with it, with many changing their manufacturing methodology to reflect that culture. These days, even if the owner wants some44 Silicon Chip thing repaired, it often can’t be, due to the non-availability of spare parts. Just the other day I had to break the news to a neighbour that their 1992era, 3-CD player cannot be repaired because I just can’t find any suitable parts for it. Such is “progress” in the modern age. Another example of this “no repair” culture is illustrated in something that happened to me recently. It is nonelectronic but the situation has many parallels in the field as well. A few months ago, I purchased a name-brand, 2-in-1 pneumatic stapler and brad nail gun from a large Australian-based hardware emporium who have several stores here in Christchurch. This tool cost $99, which I thought a sensible price for a quality tool made by a well-known tool manufacturer. I especially like the bright-green plastic fittings, a trademark colour scheme this company uses on all their tools. The nail gun came with 250 18 gauge staples and 250 18-gauge brad nails and I bought it specifically to tack building paper onto the walls while renovating my latest workshop. With this pneumatic staple gun, the job went very well, however even before I’d used up all the staples that came with it, the hard-plastic ‘bumper’ that clips onto the end of the barrel of the stapler broke in two and fell off the gun. This plastic piece offers some protection to the surface of the material you are stapling or nailing and assists in spreading the pressure applied when you push against the work, which you must do in order to activate the trigger mechanism and fire in the staple. Without the plastic bumper on there, the end is quite small and being metal, easily marks timber or other softer surfaces. Indeed, when I tried siliconchip.com.au it without the bumper, the bared end tore the building paper on two out of five staple attempts, meaning I could no longer use it for this job. I consider myself reasonably good with tools, that is, I don’t habitually thrash them or put them under any more duress than they are designed for. This is the line I took as part of an explanation email to the support and spare parts departments of this company in an effort to obtain a replacement plastic bumper. Surely I couldn’t be the first one this had happened to? I thought that this must happen often enough to warrant a healthy store of spare bumpers, made available through the retailer or website parts department. But no, the bumpers aren’t available as a spare part. I had to email back to make sure. Did no one else ever have this happen? I mean, the tip is plastic and takes a lot of hammering and once broken, the tool is a lot less functional, especially on surfaces we don’t want marked. I’d pretty much have to junk the tool if I couldn’t find an alternative solution. Then again, I shouldn’t have to do that at all… The first thing I did is what any self-respecting serviceman would do; I tried to repair it. After cleaning the two plastic pieces with isopropyl alcohol to remove any oils and grease, I applied a liberal amount of 24-hour epoxy resin and taped the cover together. I left it for two days to be sure the epoxy had completely set. It lasted all of ten staples before falling apart along the same fault line. Disappointed but undeterred, I went to the same local hardware emporium and bought the strongest two-part glue I could find. I also tasked the tool guys there about the bumper only to be told the same story. This time I glued the piece in place, using a U-shaped piece of copper shim material formed to bridge the gap at the top and being careful not to get glue into any of the workings of the gun. To hold it all together, I added another layer of glue to the outside and wrapped the whole thing in a couple of layers of heavy-duty electrician’s tape, pulling it as tightly as I could to squeeze the glue without breaking the tape. As it dried, I periodically worked the staple mechanism to ensure it wasn’t going to end up stuck together. siliconchip.com.au After another 48 hours, I trimmed the tape back with a scalpel and carefully cleaned off any dried glue that would foul the end of the bumper. Since then, I’ve pumped at least 4,000 staples and brads of various sizes through the gun and it is still going strong. However, the story didn’t end there. After that initial email stating there was no such spare part, I wrote another email in response saying how disappointed I was that such a fragile and necessary part was not available and that the tool was virtually useless to me without it. I said that I expected more from this particular company and considered it unfair that after paying over the odds for a better-quality tool, I actually ended up using it for less than a fraction of the time it should have lasted me. I told them I’d intended to use it for woodworking and joinery after the building paper job but that now looked to be out of the question. It was about this time I decided to try and repair it, and since I ended up with a working nail gun, I considered it a win, no matter the company’s response. A few days later, I got a call from an Australian customer support representative. She asked for my postal address, which I gave, and she assured me the matter would be resolved. I thought they’d scraped up some bumpers after all and were sending them over, though it was a bit moot now I’d glued mine on. However, that repair wouldn’t last forever, so I’d at least have another bumper to replace it with. A few days later, a courier arrived with a large box, and I immediately thought this was a ridiculous amount of packaging for a couple of tiny plastic parts. Perhaps they sent a hundred of them! When I opened the package, they had sent me a whole new nail gun! I’m extremely grateful for the amazing customer service but I can’t help feeling they could simply make spare bumpers available and save themselves shelling out a lot of extra nail guns! Medion computer repair B. P., of Dundathu, Qld locked horns with a faulty Medion desktop computer. It was a time-consuming exercise but he eventually got it going again . . . I was recently given a Medion computer by a friend, after they bought a new computer. At the time, I was told that it no longer worked and that they would dump it if I didn’t want it. When I first saw it, I immediately noticed that the card reader door on the front panel was missing, as it had been accidentally broken off some time ago. However, the computer did have a Windows 7 license, making it a suitable candidate for repair, so I grabbed it. When I got the computer home, I immediately decided to check to see what was wrong with it. I began by removing the side panel and unplugging all non-essential items from the motherboard. I then removed the RAM and cleaned the contacts before refitting it and turning the machine on. It initially started up but then halted with a CMOS error. As a result, I got into the BIOS set-up, altered some of the settings and rebooted it. That didn’t fix it, unfortunately. Instead, it was now completely dead. All further attempts to get it working, including replacing the RAM with known good RAM, failed and it was now clear that the motherboard would have to be replaced. I then checked the hard drive on another computer. It was also dead, so something major must have happened to the computer to cause all these hardware failures. Before going any further, I next decided to look into replacing the missing front-panel door. After all, there would be no point doing anything else to the computer with the front of it looking the way it was. Much to my frustration though, the front panel proved difficult to remove, because the optical drive was blocking access to one of the retaining clips. However, by using a thin knife, I was able to pop the clip and then remove the panel. I knew I had another Medion computer stashed in my shed and after some searching, I was able to locate it. This machine was considerably older than the one I wanted to repair and had a different front-panel layout. The case was also badly rusted at the back and the front power button was missing, so I didn’t mind wrecking it for parts. I removed the front panel from the older case, retrieved the door panel and door and compared it with the door panel from the newer case. It was significantly different, being some 6mm deeper than newer unit, so I completely dismantled the replacement door panel and trimmed it down to January 2017 45 Serr v ice Se ceman’s man’s Log – continued size. I then reassembled it and fitted it to the newer panel. This worked out well and in fact, the front of the computer looked completely original. My next step was to see if I had a motherboard that could be used as a replacement. As it turned out, I had a very similar AMD-based motherboard that looked like a suitable candidate. This was a Gigabyte GA-880GM-USB3 Rev 3.1 motherboard with an Athlon II Quad Core 3.0GHz CPU, whereas the original motherboard contained an Athlon II dual-core 3.1GHz CPU. Provided I could get the replacement board working, it would have a bit more fire-power than the original unit. I then rummaged through my box of DDR-3 RAM and managed to find four Kingston 2GB modules. I installed these in the replacement motherboard, fitted the board inside the case and ran Memtest 86+. It all passed with flying colours, so that was the RAM sorted. I then cleaned and swapped over the original heatsink and fan from the faulty motherboard, as both were slightly larger than the stock AMD units on the replacement board. The fan was also fitted with a clip-on trumpet and this actually lined up better with the holes in the side panel than the original trumpet. I also had a spare 500GB Seagate hard drive, so I installed that and then went about installing Windows 7 on the computer. Once finished, Windows 7 booted up without complaint and when I checked, I had 30 days left to activate it. I then installed the drivers for the motherboard and the inbuilt WiFi card, which is located behind the front panel. After a few days of testing to make sure everything was OK, I then activated Windows so that the machine was now ready for use. However, there was now a further problem. The original motherboard carried two internal USB 3.0 ports and there were two cables plugged into these: one running to a front-panel USB 3.0 socket and the other to a USB3 back-up drive connector on the top of the case. Unfortunately, these internal ports were lacking on the replacement motherboard. I wanted to be able to use a USB 3.0 port on the front of the computer, so 46 Silicon Chip I had to think of some way of to connect it up (the back-up drive connector was less important). A search on eBay soon turned up a USB 3.0 PCIe x1 card with two external rear USB 3.0 ports and an internal 19-pin header at the front of the card. This would be ideal, as I had already previously seen a 19-pin USB 3.0 plug to two USB 3.0 ports adaptor on eBay. In the end, I ordered two adaptors and two cards and I waited for them to arrive. Once the parts arrived, I installed one of the cards and plugged in a 19-pin to two USB 3.0 ports adaptor and connected the two USB 3.0 cables. I then turned on the computer and grabbed the card’s driver CD. Unfortunately, finding the correct driver on the CD proved to be anything but straightforward. The CD contained several drivers, so it was a trial and error process until I found the correct one. Once that had been done, the two extra USB 3.0 ports were fully functional and ready for use. Unfortunately, after about a week, the computer suddenly stopped working. I soon found that the replacement motherboard had failed completely, which was a real blow after all the work I’d put into it. I had another look through my shed and this time I found an old rusty case with a Windows XP license. It also had a Gigabyte GA-880GM-USB3 motherboard, so I thought I would use this. I then noticed that even though it was exactly the same model, this was a Rev1 board, whereas the one in the Medion was a Rev3.1 board. The main difference was a slightly different layout near the RAM slots, with the Rev1 board also having one IDE connector and one floppy drive connector, whereas the Rev3.1 board did not have these additional connectors. Other than that, the two motherboards were almost identical, with the same number of SATA ports. However, why do a simple swap when there’s an opportunity to complicate things! I knew I had another Rev3.1 motherboard in another computer that I’d just upgraded, so I decided to remove it from that computer and use it in the Medion The Rev1 motherboard could then be slotted into the donor computer. This would be a more practical arrangement because the donor computer had a moulded floppy drive slot in its front panel. By substituting the Rev1 motherboard, I could then connect the floppy drive again. The motherboard swap went smoothly and both computers were soon back in operation again, each siliconchip.com.au Roberts DAB Radio Repair Fixing a simple fault can sometimes involve a lot of disassembly work, as G. C. of North Ryde, NSW found out when he tackled a friend’s DAB radio. There’s always the risk of breaking something in the process. I was recently asked by a friend to have a look at a 5-year old DAB radio which, after daily use in the bathroom, was refusing to switch on. The radio in question was a Roberts Ecologic 4 mains/battery set. Its owner said that it was a good performer and that he would like to have it fixed, if possible. Working on modern electronic appliances is not my favourite pastime, as I much prefer restoring valve equipment. Despite this, I agreed to have a look at it as a favour owed. Given that this is a digital set, my initial guess was that the fault was in the push-on/push-off power switch itself or with the associated logic. If it were the latter, then I was hoping the requisite part would be readily obtainable. Roberts is a British company, although the radio itself is clearly made in China. Before spending time on the radio, I decided to Google the symptoms and found that this was a very common fault, with many disgruntled owners saying that the response from Roberts was to send the radio back to them for repair, along with the specified fee. I couldn’t find a service manual online so I emailed the Roberts Technical Department, requesting an explanation of the notoriously common fault to help me fast-track a local fix. They replied that I should send the radio to them for repair. It was patently obvious I wasn’t going to get any leg-up from the manufacturer. At this stage, I decided to open up the set. This involved the usual routine of removing a dozen or so deeply-buried screws using a smalldiameter, long-shafted screwdriver. The screws were of assorted gauges and lengths, so I made a note of which went where. With the case split in half, I was confronted by a power supply board in the rear section, adjacent to the battery compartment, from which a number of wires ran across to two main PCBs: one for the radio function and its associated knobs and pushbuttons and the other for the stereo amplifier function. These two boards are mounted back to back, with an insulating sheet sandwiched between them. This sheet consists of a piece of aluminium foil covered on both sides with its original CPU and RAM. However, I did have to reinstall the USB 3.0 driver in the donor computer, because the Rev1 motherboard has a different USB 3.0 chip. Apart from that, all the other drivers for both motherboards were identical and there were no complaints from Windows about the motherboards being changed. Although this had all been a somewhat time-consuming exercise, the end result is a refurbished, reasonably-modern computer that would have otherwise gone to scrap. It may not be up to gaming but it’s perfectly adequate for internet browsing, emailing and other similar activities. And because I got it for nothing and I used mainly recycled components for the refurbishment, it cost me much less than the price of a new computer. Nothing to RAV on about B. C. of Dungog, NSW recently turned auto-electrician when he took 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. siliconchip.com.au by black insulating material. The upper PCB is made of fibreglass and contains mainly SMD components. By contrast, the lower PCB is phenolic and contains throughhole components. A plethora of wires run between these boards and to the stereo speakers. As well as those unpluggable cables, there were three wires soldered to metal inserts in the case which presumably provide shielding. It’s not what I’d call an elegant, optimised design by any means. The on/off control is a 6 x 6mm pushbutton switch which is soldered to the upper PCB. Without further disassembly I was able to get my DMM across its terminals and confirm that it was functional, so the problem lay elsewhere. Further Googling found just one technical reference to the fault and it laid the blame on a 4013 dual-D flipflop. That made sense, given that a momentary on/off switch needs a memory of its last switched state. And a dual-D flipflop is a typical way to accomplish that. A small dental mirror allowed me to see that there was a SOIC chip soldered adjacent to the power switch, so I proceeded to remove the PCB sandwich from the case, layer by layer. Removing the lower PCB and the insulating layer was comparatively easy. continued next page on an aging Toyota RAV4 with speedo, tacho and air-conditioning faults. A friend’s daughter has owned the Toyota RAV4 (a late 1996 model) for a number of years now. Unfortunately, due to its age (20 years) and high mileage, various problems have needed attention in recent times. Recently, I was asked if I would look at problems with the speedometer, tachometer and the air-conditioning/ heating system. And so, on a recent visit to her parent’s place, I took the opportunity to examine the vehicle. By this time, the speedo had completely failed and she was using the GPS function on a smart-phone to monitor the road speed! Fortunately, the Nippon Denso instrument panel is relatively easy to remove from this vehicle. I then retreated with the faulty unit to my workshop, January 2017 47 Serr v ice Se ceman’s man’s Log – continued However, removing the upper PCB involved detaching the fascia from the case in order to reach three screws hidden underneath it. Unclipping the fascia without breaking it was a real chore but I was eventually able to reach the PCB. A quick check with a DMM revealed a short between pins 7 & 14 of the 4013. Fortunately, it’s a fairly common chip costing around 50 cents and a mate with an SMD reflow station kindly replaced it for me in a 60-second manoeuvre. With the new chip installed, I reconnected everything on the bench, applied power to the system and pressed the power switch. Bingo! – placed it face-down on a towel and removed the speedo and tacho heads from the main PCB assembly. Each head in turn had a small PCB soldered to its rear containing a meter movement with two coils. The speedo head (PCB – 0680) carried a 24-pin ND SE236 DIL IC but that wasn’t the cause of the problem. Instead, there was a dry solder joint on one of the four coil pins (two pins per coil). The same problem was evident on the tachometer head PCB. This board carried a 16-pin D056956-0240 DIL IC and it too had a bad solder joint on one of its four coil pins! Since these failures were due to vibration, I decided to blanket solder all the joints on both the speedo and tacho PCBs to ensure future reliability. It was then just a matter of reassembling the instrument panel, taking it 48 Silicon Chip the LCD displayed “ABC Radio connecting . . .” and a second or two later, sound came through the speakers. As I reinstalled the PCBs inside the case and wrestled once again with the fascia, I began thinking that this hadn’t been too painful a job after all. And then it happened! The on/off button itself was attached to the upper part of the case by a flimsy web of plastic, about 1mm across, which acted as a sort of spring. As the switch’s own button was only about 2mm high, the on/off button activated it by way of an integral plastic shaft about 15mm long. Unfortunately, as I attempted to back to my friend’s house and refitting it to the vehicle. A subsequent road test then showed that both the speedo and tacho now worked perfectly. It was now time to troubleshoot the air conditioning/heating system! Switching the fan speed to each position (with the ignition turned on), revealed that the blower fan motor wasn’t running at all. Removing the glove box and some trim items gave access to a subcontrol panel and the blower fan motor assembly. A quick check with a DMM then indicated that +12V was present at the blower fan input connector, so it wasn’t a supply problem. I unplugged the unit and connected a 12V 7Ah gel battery directly to the motor input connector via some suitable test leads but there was still no line the button up with the switch, while simultaneously keeping the fascia in place, both the plastic web and the shaft disintegrated. There was nothing left to salvage or glue. Not happy, Jan! After the customary string of choice words, I thought about my options. As there was little chance of reconstructing the original plastic shaft and spring arrangement, I decided to fit a new tactile switch with its own long shaft. Fortunately, I was able to source one with a 17mm-long shaft (or actuator) and that was long enough to poke up through the hole where the on/off button resides. And so, once again, I had to remove the PCBs in order to solder in the replacement switch. The next task was to gently ream out the button itself and fill the inside with Knead-It, a fast-setting epoxy putty. Once it had set, I then used a slow drill to make an indentation into the putty just deep enough to accommodate the top of the switch’s shaft, while ensuring that the on/off button was at the correct height to remain in place in its hole. I then proceeded to once again wrestle with the fascia and this time it all went together without any drama. The new switch has a more positive feel about it, and my friend was very happy to have the radio back in working order. response. As there were only three PK screws securing the blower motor assembly in place, it was easily dropped out for closer examination. Removing a small air vent cover then allowed access to the rear of the motor. Close examination of the motor with the aid of a LED torch subsequently revealed that the brushes and commutator were both badly worn. And that meant that a replacement blower motor assembly would have to be obtained and fitted. A search on eBay uncovered two locally-available secondhand units, both at a reasonable price. One of these was ordered and I bench-tested it before fitting it to the RAV4 during my next visit. This replacement unit completely restored the vehicle’s airconditioning and heating system to normal operation. SC siliconchip.com.au