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SERVICEMAN'S LOG It would be a waste of parts Dave Thompson One of the bigger challenges we face as electronic servicemen is finding replacement parts. It’s bad enough that many parts are no longer being made, but it seems that many manufacturers go out of their way to make it difficult for repairers. Some manufacturers use a combination of methods to frustrate us: obfuscating critical component values, using single-use or anti-tamper fasteners, withholding data sheets or circuit diagrams, or by using proprietary parts and either not making them available, or restricting access to them via ‘official’ repair agencies. Gone are the days when comprehensive back-end parts supply networks supported products for years after they were sold. Note that some companies do not use this model. BMW, for example, still stock or supply parts for every car they’ve ever made. Having said that, if you’re cynical, you might think that this is part of their business model. Who else do you know that makes cars with rod bearings that are maintenance items! And don’t get me started on the plastic water pump impellers or selfdestructing VANOS pumps... But at least you can fix your BMW when it breaks. That’s something. There are other ‘good guys’ out there, include the likes of Kenwood and a handful of well-known home appliance manufacturers. Admittedly, even for these manufacturers’ products, getting hold of some of the rarer parts for older models can be expensive or difficult (or both); but at least they are available. It’s a shame more companies don’t do the same; instead of us repairing their products, they prefer we simply dump them and buy a new one, which has never made sense to me. Wasteful business practices If I buy a product that fails and cannot be repaired, I am far less likely to buy another one made by the same company. My knee-jerk reaction is to take my business (and money) elsewhere. So it may help them make a quick buck now, but it’s going to cost them in the long run. That’s not to say the next manufacturer’s product won’t be exactly the same, but at least I’ll feel empowered about not throwing good money after bad. I’d also be more inclined to do my due diligence next time, and buy instead from a manufacturer who offers ‘real’ after-sales service and support. But perhaps more importantly, the amount of waste this generates is horrendous. Over the years, my microcompany has recycled (where possible) or dumped tonnes of plastics and metals, some of which is probably quite toxic to the environment. Multiply that by millions, and the result is mountains of e-waste. I’ve said it before; throwing away an entire device (for example a printer), for the sake of an unobtainable 10cent part, is disgraceful; something must change. Items Covered This Month • • • • A lack of replacement parts leads to much waste An old TV repair A series of Diesel Peugeots HP4350dtn printer repair *Dave Thompson runs PC Anytime in Christchurch, NZ. Website: www.pcanytime.co.nz Email: dave<at>pcanytime.co.nz siliconchip.com.au Australia’s electronics magazine April 2020  57 Usually, it is those of us at the front lines who have to break the news to incredulous owners that their appliance is now junk because we can’t get some component for it. In many cases, even if we can get a circuit diagram, or are clever enough to change the design to allow newer parts to be used, the repair costs often exceed (or at least, come close to) the cost of a replacement unit. When it comes down to it, the less-expensive choice usually wins. I don’t think I’m being too dramatic if I say things have to change. Most manufacturers of old (say, one generation ago) would be appalled at the built-in obsolescence and the sheer waste of materials that modern companies create. My suggested remedy is simple: if a company makes and sells a product without a reasonable life expectancy, or fails to provide spare parts or information to support it, they should then be liable for that device when it fails. This would mean the company has to take the products back at endof-life and be made to dispose of the waste responsibly. Obviously, this would take some doing, but at least if they sell junk that lasts a year, they then have to deal with the fall-out from it. I know what you are thinking; these people could simply sell their toxic mountains of rubbish to a developing country for ‘processing’ and wash their hands of the whole thing, and of course, this is already happening. But a well-run system would make them prove that the items had been disposed of properly. Perhaps then, manufacturers would put more of a focus on long product lifespans and sustainability, and less emphasis on making quick profits. This would no doubt result in more expensive hardware, but I, for one, would be happy paying more for this. Anyway, if you pay 50% more for a product which lasts twice as long, you’ve come out ahead. almost every unit. The company must have known of the problem for years, especially as existing supplies of what spare PCBs there were available dwindled. Instead of admitting to the problem and producing more spares, to keep these not-insubstantial instruments going at very minimal cost, they chose instead to try to coerce owners into buying a brand new unit. I think that’s an immoral and unethical way to treat your customers, and wasteful to boot. The rub is that many of these pianos aren’t creaky old junk. They are well-loved pieces of furniture and most are still 100% working except for the failing flexible PCBs. It didn’t take me long to identify the problem; even a cursory Google search revealed many dozens of irate owners in the same position. There was talk of class-action lawsuits, but a rag-tag bunch of end-users have no real chance against some multibillion-dollar conglomerate with deep pockets. Even when such lawsuits are successful, the damaged parties usually get a pittance. The only real winners are the lawyers. The result is a group of people who will likely never buy another piano made by that company. So does this make for good business practice? The company seems to do all right, regardless. So I guess they got away with it. also threw up some parts challenges. The amp used a couple of output (power) modules I hadn’t seen before. Amplifier modules were all the rage back in the 70s and 80s. Possibly the best-known of these was the Sanken range. They made a family of hybrid thick-film stereo and monaural units. They look like a huge, flattened integrated circuit, with either a pressedmetal or moulded-plastic body and with legs protruding (usually) only from the bottom edge (making them effectively SIL or DIL packages). I used plenty of them in my homebrewed amps back then, and while the specs might be a little iffy compared to today’s offerings (or even discrete transistor-based circuits of the time), they still hold up pretty well. The SI-10X0 mono versions especially suited my needs, coming in 10W, 20W, 30W and 50W flavours. I got the most mileage from the SI-1050G, the 50W version. This was especially good for guitar, bass and general sound reinforcement applications. They were great bang-for-buck, being very robust, relatively inexpensive, able to run from a single or split power supply and requiring just a handful of external components to create a halfway decent power amplifier. This meant that the output stage could be kept pretty much the same from amp to amp, with only the Case study two Recently, I had an almostvintage stereo amplifier through the workshop, and this Case study one The reason for the above rant is a few jobs I’ve had through the workshop of late. One was an electric piano, which would have been landfill fodder if I hadn’t been able to manufacture a replacement for the dead flexible PCBs. From all accounts, these failed in 58 Silicon Chip Australia’s electronics magazine siliconchip.com.au preamp sections needing tweaking to suit the amp’s intended purpose. This also made them ideal for a generalpurpose workshop amp. Sanken made large quantities of these devices over a fairly long period, so there are still many floating around today. Most varieties are available at very reasonable prices from the usual surplus and second-hand outlets. Some are even NOS (new, old stock) parts. I have bought dozens over the years when they’ve come up on local auction sites; I even scored a couple of 30W modules from a home-built hifi amp I was given at an estate sale. So when I encounter modules in an older amplifier, they are often Sankens of one sort or another, meaning that my stock of the more common modules frequently comes in handy. If I don’t have the right one on hand, I can usually source it from the likes of eBay or direct from China. However, with this recent amp, the modules were not made by Sanken but rather, RCA. Worse, they had no model numbers visible. Faded and missing part numbers are another test for servicemen working on older gear. As a youngster, I was sometimes given boxes of old components from defunct workshops. Many had no markings, or the numbers had faded or rubbed off from rummaging. Often, with the part held at an angle to the light, a quick huff on the component would show an outline of the markings (the moisture in one’s breath adhering differently to the various textures on the part’s surface). Sometimes, a dab of moisture from the soldering sponge similarly revealed enough information to allow one to make an educated guess. These days, we have good-quality USB microscopes which can also help. While these older methods still work, for simple components like transistors, I often just use a component tester. As long as the unidentified component is still working, I can connect a suitable tester and it will (hopefully!) tell me all I need to know. However, these testers aren’t much chop on most integrated circuits, including old audio modules like this one. If someone really wants to prevent their components being identified, they are usually successful. (It isn’t uncommon to see component siliconchip.com.au labels ground off the top of packages!) In this case, I resorted to asking my old friend Google. Using the image search, I soon came up with a pretty good guess as to its identity. The mystery components appeared to be RCA TA8651As, sometimes marked HC2500. This is a ‘vintage’ 100W audio amplifier module, similar to the Sanken types. Fortunately, there are several used and NOS versions of these sold by vendors on overseas auction sites, though a good number of these will not ship to us down here in the dominions. After a few emailed enquiries, I managed to find someone who would ship them, complete with a data sheet, at a reasonable cost. So this particular amplifier was repaired and the owner happy. But that isn’t always how these stories turn out. In more than a few cases, I’ve hit a dead-end as the required parts are just not around anymore, meaning that the device either has to be modified and rebuilt with different parts, or consigned to the scrap heap. For example, I was asked to repair an older Pioneer stereo system that also used modular output devices, also unmarked and unknown to me. This was back in the pre-internet and pre-search-engine days (practically pre-history!), so I could not conduct an image search and had limited access to circuit diagrams. Back then, manufacturers seemed to give out circuit diagrams freely, although in this case, the owner couldn’t put his hands on the one that came with this unit. So, in the end, I could not identify them. The customer wanted to retain the unit, as he’d spent a lot on setting up his system and the amplifier matched the rest of his components. I ended up replacing the output sections completely with Sankenbased versions, complete with purpose-made PCBs. I suppose it sounded close enough to the original – the customer was happy with it – but of course, the modification likely killed any value it might have had as vintage hardware. Repairing a poorly-designed guitar amp More recently I had a 100W solid-state guitar amplifier in for repairs. This wasn’t an old amp, but it wasn’t exactly new-fangled either. Australia’s electronics magazine It is just a typical, run-of-the-mill combo with one 12-inch speaker and the amp itself sitting inside a folded metal chassis-mounted at the top of the wooden case. But it has a design quirk that makes it difficult to live with long-term. The amp’s output transistors are mounted to a compact heatsink assembly, tacked onto the rear of the chassis. While the heatsink looks quite beefy, it is barely adequate for the job, especially if the player is thrashing the amp at higher volumes. Design constraints meant there was no room for more heatsinking, so the manufacturer added a couple of cooling fans instead. This may seem like a good idea, but the problem is that smaller fans (in this case, 76 x 76mm) have to run at very high speeds to move enough air, and this means noise, especially once the fans get a bit older. These fans look similar to CPU cooling fans of the same era, and those fans used to wear out and get noisy reasonably quickly too. These days, CPU cooling fans (in desktops at least) tend to be bigger, with a more efficient blade design, and they run slower. While most are around 100mm, it isn’t uncommon to see 120mm fans cooling some of the higher-spec processors. Small fans may be able to move just as much air, but the noise they produce can be very distracting to some people. Larger, slower fans still produce noise, but generally not as much and at less annoying frequencies, even while they move the same amount of (or more) air. The fans in this guitar amp are thermostatically controlled, so they speed up as the output stages get warm, but that doesn’t take long even at normal practice levels. When the fans kick in, you have to crank up the amp volume to hear over them, which makes the amp work harder and the fans run faster, creating a vicious cycle. Recording in even a rudimentary studio would be out of the question with this amp, at least if you wanted to mic up the built-in speaker. It is possible to avoid using a microphone altogether by running a line-out from the amp’s preamp out socket, or by using a direct injection/ DI box and piping the signal straight into the mixing console. But many guitarists prefer to capture the combined sound of their amp and speaker, April 2020  59 which inevitably means sticking a mic in front of it. Since the customer wanted to record this way, we need to find a viable solution. My first thought was to replace the fans, but of course, there are no identical replacements to be had. Because the fans in all these amps wear out, genuine replacements have long since dried up. Using CPU fans instead is the only feasible route, but it means a bit of sheet-metal working and tinbashing, which the customer wasn’t overly keen on. After much gnashing of teeth and wringing of hands, we agreed that this was the best solution. I promised him that it would look as factory as possible, and with that pledge set to work. I decided to use larger fans to quieten them down a bit; specifically, 120mm models. So I’d have to trim the existing holes out to almost the edge of the metal case. The old fans sat over two circular holes; I reasoned that re-shaping these holes to a square would allow more airflow through, so I marked the lines out and then cut out the extra material using a Dremel rotary tool fitted with a small cutting disc. I finished off the edges with files and sandpaper, then marked and bored new mounting holes. I used eight standard M5 x 10mm PC fanmounting screws to hold the fans to the chassis. The old fans were connected with inline connectors, which I didn’t have, so I cut them off and soldered the new fan leads to the PCB, finishing things off with cable ties and heatshrink tubing. I broke out my workshop Telecaster and played the amp until the fans fired up. The noise difference was remarkable. The customer was very satisfied and as far as I know, still uses the amp today. That sure beats chucking it in the bin! a bright young spark (with much to learn) by one of my instructors, as he used to work for that company. When I joined, I was the junior of the western suburbs group. This group had some of the company’s best and most experienced servicemen, so I thought myself lucky to be in such exalted company. In those days, we used two-way radios to send servicemen to the next job – this was an open channel so everyone could hear what was said. If you got a radio call to phone the field service manager, it usually meant you were about to get a rocket over something. I was surprised upon receiving such a call, as I thought I had been a good boy that week. I was even more surprised when I was asked to go and have a look at a TV set that was usually handled by our group’s most senior technician. Obviously, our field service manager did not want to bruise any egos by letting everyone know he was sending ‘the kid’ to have a look at it. This lady was complaining that the set had a bright dot in the middle of the screen, and she could not see her favourite show properly. Most TV sets in those days were under a service contract; this one had been subject to many callbacks in recent times. Each time, no fault was found. I did not get off to a great start with the lady when she opened the door and exclaimed: “now they are sending children to fix my set!” But all was forgiven as she made great tea and scones. It was company policy that every call-out was recorded on a card in the back of the set. The card had a description of the work done on the set, including the components used and the signature of the attending technician. I was astounded by the number of calls recorded on this set, not only by our group’s senior serviceman, but by other very experienced technicians and the field service manager himself; all “no fault found”. The set had even been sent to the workshop twice and returned with “no fault found”. The trouble appeared to have started after the picture tube (CRT) had been changed. It was not unusual that old picture tubes would produce a dot in the middle of the screen when the set Old TV repair V. R. S., of Kelvin Grove, Qld is perhaps the only technician we know who solved a longstanding problem in a TV set without having to replace any components or make any adjustments. He didn’t even need any tools! Read on to see how he did it... In the late 1960s, I was in my twenties, and I worked for a large TV service company in Brisbane as a field technician. I was recruited from college as 60 Silicon Chip Australia’s electronics magazine siliconchip.com.au was switched off, or if the spot swallower circuit was faulty. The components in the swallower circuit had already been changed. I checked these against the circuit, and they were all the correct values. If the EHT (extra high tension) 15kV regulation were the problem, the picture would grow in size as the brightness was increased. There was no sign of this, so this left the new CRT as the culprit. I turned the set on and off several times but could not fault it. The set had been on for some time, so I asked the lady to leave it turned off for an hour, and I would return and try the set from cold. It took me more than an hour to return, and by that time she had given up and turned the set back on to see the midday news. I then had to reassign the job for first up the following morning as I was not available that afternoon. I pleaded with the lady to leave the set off until I arrived. The next morning, you guessed it, the set was on when I arrived – frustration was building. Again, I asked her to turn the set off and leave it off until after midday. She promised she would, but I had to be back before her favourite show began at 3pm. On arrival at about 2:45pm, I walked over to the set and turned it on, and all appeared to be functioning normally. Turning to the lady, I said: “I am sorry, I can’t find anything wrong with your set”. Her reply was: “are you bloody blind, can’t you see the white dot in the middle of the screen?” Oh! I then did an about-face, walked over to the window and drew the blinds, thereby removing the reflection of the window from the screen. The sun only shone on that side of the house in the afternoon. It appears that I was partly correct. The problem arose when the tube was changed, and the lady asked the technician to help her move the set to the opposite side of the room. It was previously under the window, where it would not reflect the incoming light. Checking the job card, I realized no-one had been there in the late afternoon. I took great delight in filling in the card with “problem found”, but deliberately not saying what the problem had been. This way, my compatriots would have to ask and I would smugly answer: “the kid one, all the others nil”! siliconchip.com.au A series of diesel Peugeot electrical repairs The TV series “Roadkill” describes a “plague car” as a car that runs fine but nobody wants it, because it’s not in fashion, it’s ugly, or it has some minor problem that is annoying but difficult to fix. You can pick them up cheap, but you’ll be lucky to sell them for more than scrap value. W. S., of Numurkah, Vic has quite a bit of experience purchasing them and fixing them up, as he now recounts... With over 450,000km on the clock, my Peugeot 405 (which I run on home-made biodiesel) was getting a bit clapped out. So when I spotted a diesel Peugeot 406 for $750, I jumped on it. It was filthy and had a few dings and rattles, but its main problem was that the speedo was not working. This prevented the owner from renewing its registration. The owner had been told that to repair it, the gearbox would have to come out. Hence the low price. After a good clean, the car started to look like something. I repaired a tie rod and a couple of other things, then turned my attention to the speedo. I found the speed sensor buried in the engine bay. It had to be removed from under the vehicle, which was not easy. It’s a two-wire reluctor. I put it on my scope and spun it, and got a nice-looking sinewave. I then put the sensor back in (again not easy), and re-checked the output, this time with the wheels jacked and the car running in gear. Again, I got a sinewave output. So at least the gearbox didn’t have to come out. This model has an analog-to-digital converter for the speedo signal behind the glove box, which I suspected was not working. But when I checked its output, I got a reasonable-looking signal. So I thought maybe the speedo itself was broken. I removed it and set up my power supply and fed it a pulse train, and it came to life. This had me quite puzzled and I spent a couple more weekends checking the wiring and re-checking everything. I ended up replacing all the caps in the converter, but the sensor, converter and speedo still would not work together. I decided to replace the speed sensor, but found that this type of sensor is not available new. It was only used for a couple of years and was replaced Australia’s electronics magazine April 2020  61 with a three-wire Hall-effect sensor. These are only around $20 each, so I got one. I had to climb under the car again, to remove the old sensor and modify the wiring to suit the new one. I found the transmission gear didn’t fit the new sensor quite right, so I 3D-printed a small adaptor. I removed the converter and re-wired everything, crossed my fingers and took it for a drive. To my surprise, everything worked as it should, and a quick check on my GPS confirmed that the speedo was accurate. I’ve now driven it another 70,000-odd km and so far so good. 406 number two A few months later, I suggested a Peugeot to a friend wanting to replace his Hilux. He wasn’t interested, but I convinced him to take mine for a drive. He came away suitably impressed, and when I told him it does 1200kms to a tank and cost me $750, that was it, he had to have one. So I found another 406 on Gumtree with an immobiliser problem for $600. I pointed out to my friend that HDI tuning in the UK will delete the immobiliser from your ECU for around $400. It turns out that the owner had taken the car to several places, but no-one knew how to fix it. The dash was still in pieces from the last autoelectrician who looked at it. That being the case, he managed to get the car for $450 and spent the afternoon putting it back together. He was about to order the remapped ECU when on a whim, he decided to put a battery in and see what would happen. The car started straight up; he drove it for about two years on biodiesel before the immobiliser fault came back. So, he ordered a new ECU with a remap and the immobiliser turned off. All that he had to do when it arrived was disconnect the battery, remove the old ECU (which is under the bonnet), plug in the new one, connect the battery and not only would it start again, he’d gained an extra 45 horsepower. The 306 I saw a diesel Peugeot 306 listed for sale on Gumtree with 160,000km. The listing said it wouldn’t start. I didn’t really want another car, but I phoned my buddy because his son (who had just gotten his learner’s permit) was looking for a car. This one had a similar story; it had been to many workshops, including the Peugeot service centre, but nobody could fix it. The car was purchased for $300 and towed home on a trailer. A new battery was fitted, and the car started straight up. The car was well looked after and drove like a new vehicle, so a roadworthy certificate was arranged. All it needed was a new tyre. But after a week or so, it stopped and refused to start. At first, I thought it was the immobiliser problem again, but the 306 is quite different from the 406. It doesn’t have a display to tell you there is a fault. I plugged in an OBDII reader which wasn’t much help, as Peugeot uses their own software called PP2000. I had access to another running 306, so I swapped the ECU, body system interface module and the immobiliser chip in the key to see if the fault would move to the other car. It did not, so I knew that these parts were not part of the problem. 62 Silicon Chip It was then I noticed that I could not hear the in-tank fuel pump coming on when the ignition was switched on. After removing the rear seat, I checked the pump by running 12V directly to it. The pump ran, and the engine started. Then I checked the wiring loom and found that there was 12V present at the pump end, but it dropped to 3V with the pump connected. After a bit of research on internet forums, I found that the fuel pump relay was a common problem; it is buried in the engine bay. I eventually managed to get the sealed relay out and then used a hacksaw to remove the cover. Once the cover was off, it was easy to see the problem: the contacts were entirely burnt off. I ordered a new relay and fitted it, but the car still would not start. There was still no voltage getting to the pump. I re-checked the wiring, plugs and terminals. It was time to buy a service manual and the PP2000 OBDII software. The software arrived, and I was disappointed to get the message “P0087 code low fuel pressure”. With the pump not running, this was just stating the bleeding obvious. So I took a look at the wiring diagram. The fuel pump relay gets 12V from the fusebox, and its ground is connected to the ECU via the inertia switch, which cuts the fuel supply if the car is in an accident. It turns out that with all my wresting to get the relay out, I must have bumped it as it was open circuit. Pushing the top reset button on this switch allowed the engine to start. I took the car for a drive, and the engine just didn’t sound right, so I plugged the OBDII reader back in and re-checked the codes with the PP2000 software. It came up with “3rd piston deactivator”, which is on the highpressure pump which is driven by the cambelt. The plug to the deactivator looked fine, but the wiring to the plug looked like someone had played with it, the insulation tape was starting to fall off. After removing the tape, I could see that the wiring had been cut and modified and the deactivator had 12V feed to it all the time. I put the wiring back to standard and the codes cleared from the ECU. The car has run reliably on biodiesel until a couple of weeks ago, when the harmonic balancer came apart. Fortunately, that was an easy fix. 406 number three I got another phone call from my friend to say that his Holden Cruze had an automatic transmission fault and wouldn’t go. Long story short, while it was still under warranty, the dealer had in the fine print that they would only pay for $1500 in repairs and the trans repair would cost around $6000. I didn’t want to go near it, but I saw another 406 on Gumtree. Again, it had a few ‘issues’; it was going into limp mode, and the climate control wouldn’t work. It was bought for $600 and towed home. I connected up my reader to its OBDII port and got what must have been 20 error codes. I reset them all, and we took the car for a drive. It still didn’t seem right, so we re-checked the codes, this time just getting one code for the MAF (mass air flow) sensor. A quick check found that the sensor had been disconnected and the plug taped up. This probably was done because if the MAF sensor is faulty, it turns Australia’s electronics magazine siliconchip.com.au the engine check light on and for some reason, disconnecting the sensor turns the light off. The sensor was removed and cleaned with contact cleaner and refitted. That fixed it; the codes were gone, and the engine ran properly again. Turning to the climate control, I found that one fuse had blown. Predictably, after replacing it, it blew again. I read up on the Peugeot forums and found the speed controller for the blower motor was a common problem. This is located under the glove compartment. Access is difficult, but I managed to remove it, and I sensed that burnt PCB smell. The plug was also melted. A new controller and plug with wiring was ordered and fitted to the car, and the fuse replaced. But the fan would only run flat out and wasn’t blowing any air out of the vents. After much investigation, swearing and frustration, I determined that the blower motor was running backwards, which was very odd. I ended up going back to Peugeot 406 number two and comparing its voltages. It turns out that the new speed controller and plug had the 12V and ground colours reversed. Brand new, out of the box, the red wire was ground and black was 12V! I fixed that and fired off a stern e-mail to the supplier; finally, the climate control worked how it should. The car went in for a roadworthy certificate; all it needed was a tail light and new wiper blades. So it turned out to be another great deal! If you are thinking of buying a plague car, be aware that Peugeots are not that common in Australia, so many garages are not familiar with them. They don’t want to put in the effort or time to fault-find problems with them. The good news is they are very common in the UK, so advice and parts are available on UK forums and via ebay.co.uk Helping to put you in Control IP65 Loop Powered 4 Digit Process Indicator The Simex SWE-N55L is a 4 Digit Process Indicator which accepts 4-20mA input signals and is loop powered. It comes with 1 Relay for alarm or control. SKU: SII-110 Price: $189.95 ea + GST IP65 Current/Voltage Input 4 Digit Process Indicator The Simex SRP-N118 is a 4 Digit Process Indicator which accepts 4-20mA, 0-5V or 0-10V DC input signals. It comes with 2 Relays for alarms or control and RS485 communications. DC 19~50V powered. SKU: SII-102 Price: $289.95 ea + GST Temperature Sensor for Temperature Instruments PT100 temperature sensor with handle. Operating range -40 to 150C. SKU: HES-150 Price: $29.95 ea + GST SZP-73 4-20mA Panel Mount Calibrator Current test set allows for generating user-defined current (in the 4-20 mA range). SKU: SII-401 Price: $239.95 ea + GST HP4350dtn printer repair D. M., of Toorak, Vic knew that it would be difficult and expensive to fix a faulty PCB in his printer. But he came up with a much easier and cheaper fix that worked just as well... I have had a Hewlett-Packard LaserJet 4350dtn printer for a while now. It’s a heavy-duty, business-grade 1200dpi laser printer and as such, comes with an embedded Ethernet port as well as USB. Recently, its Ethernet port failed, so I could not use it over my home network, only via direct USB connection. This is apparently a known problem with these printers; the problem develops in their main control board, known as a “formatter” board. Instead of replacing the formatter board, which otherwise worked apart from the Ethernet section, I found it was much easier and cheaper to plug an HP620N JetDirect print server card into one of the printer’s EIO (Enhanced Input/Output) accessory card slots. I purchased this from overseas via eBay for less than $20 delivered. Once I installed the card, I plugged in the Ethernet cable and the printer immediately worked over the network; no additional configuration was needed. The card took over the failed Ethernet function of the formatter board. So an oldish but extremely robust and economical printer was saved from the scrapheap for a small outlay. SC siliconchip.com.au DA284 Pressure Compensation Valve Prevents pressure differentials in encIosures with a high degree of protection are a result of internal and external temperature changes. SKU: SPE-200 Price: $13.95 ea + GST Conductive liquid level sensor Simex DRS-303 is a liquid level sensor for conductive liquids. Ideal for use in sumps, water tanks and detect water leaks. SKU: SIS-001 Price: $109.95 ea + GST N322-RHT-24V Temperature & RH Controller 24 V Panel mount temperature & relative humidity controller with sensor probe on 3 meters of cable. 2 independent relay outputs. 12 to 30 VAC or DC powered. SKU: CET-108 Price: $235.00 ea + GST For Wholesale prices Contact Ocean Controls Ph: (03) 9708 2390 oceancontrols.com.au Prices are subjected to change without notice. Australia’s electronics magazine April 2020  63