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SERVICEMAN’S LOG Batteries, monitors, lights and audio Dave Thompson is once again busy doing whatever he does when he disappears: fighting an alien invasion, creating a new sheep hybrid, or practicing his haka – we aren’t sure which, but it must be one of those. Anyway, in the meantime, Bruce Pierson has been very busy in his shed fixing everything that comes across his bench, so here are some of the things he has repaired lately. To start things off, my son asked me if he could borrow my battery charger because his had stopped working. I asked him to bring it over and I could see that it was a switch-mode type, which are sometimes tricky to fix, but I said I would a look at it. I started by removing the four Phillips-head screws on the bottom and split the case apart. Thankfully, they didn’t use ‘tamper-resistant’ screws as is so common these days! I had a good look over the circuit board. All the electrolytic capacitors looked OK, with no bulging tops, so I turned it over and examined the copper side with a magnifying glass to check for dry joints, but there were none. In fact, it looked as if it were quite new, probably because it was. It was a change from the older items I usually work on. I got out my ESR/Low Ohms Tester from Electronics Australia, February 1996, that I built from a Jaycar kit. It indicated that all the electrolytic capacitors were good. This device has been very useful over the years for finding faulty electrolytic capacitors that showed no external signs. The MK II version of this tester was featured in the Silicon Chip March & April 2004 issues (siliconchip.au/Series/99). 88 Silicon Chip Next, I got out my In-Circuit Transistor, Diode and SCR Tester to start testing all the two- and three-legged semiconductors. I started with a diode, but the tester was not working correctly. It was flashing very dimly and slowly, then stopped flashing, with one LED lit dimly. It was a sure sign that the battery had gone flat since I last used it. I built it from a Jaycar kit of an Electronics Australia project from September 1983, and it has proved very useful. When I tried to remove the 9V battery, the negative terminal came off the battery. It took some effort to remove this detached terminal from the battery connector, but I eventually got it off. With a new battery fitted, I could continue testing. Nothing showed up as faulty. I noticed that near the battery leads there was a component that was likely some sort of SCR. I wondered if it might be faulty. I tested it, but no matter how I connected the leads from the tester, it came up as an open circuit. Well, that must be it. I used my 20W soldering iron to remove it from the board and tested it again with the same result. Now I had to identify it so I could order a new one. The writing on the device was almost unreadable, but I thought I could make out IRF724N. I looked on eBay for this and found nothing suitable. A Google search for the component gave many hits for IRFZ24N, so I guess what looked like a 7 must have been a Z. I searched again on eBay and ordered five from China for just over $5. It took only 12 days to arrive. This is a 55V, 17A Mosfet so I was surprised the original failed as it seems quite robust. I soldered it to the board and clipped the excess leads off. It mounts in the top-left corner of the circuit board, on the left side of the battery cables. I decided to test the charger before reassembling it. I set the charger on the bench with a spare 12V SLA battery connected, plugged it in and switched on the power. After a couple of seconds, the charging LED came on next to the power LED, so I knew I could reassemble it and give it back to my son. I checked the Supercheap Auto website to see if this charger was still available, but it was not. Similar chargers cost between $60 and $100. My son has had this charger for several years now (it came with the caravan he bought). His caravan battery is charged by two solar panels, with the charger being used to top up the battery when necessary. Australia's electronics magazine siliconchip.com.au The internals of the Samsung SyncMaster 2253BW monitor. The remains of the lizard were very clearly present when the back was taken off. It cost just over $1 to repair the battery charger, a considerable saving compared to buying a replacement charger. Saving a ‘new’ SLA battery I was sorting out some things in my shed when I came across a new UPS box that had a brand new UPS in it. I didn’t remember having this, so it must have been in the shed for a very long time. I could tell by the weight of the UPS that it had a battery in it, which was a bad sign. These SLA batteries must be kept charged because when the voltage drops below a certain point, they will refuse to charge again. In that sense, they are worse than flooded lead-acid batteries. Of course, car batteries should never be in a situation where they are allowed to become dead flat, as it shortens their life. Still, usually you can recharge them if they go flat. I took the SLA battery out of the UPS and tested the voltage with my multimeter; sure enough, it read 0V. That was a waste of a new battery. I was just about to recycle it when I thought I would connect my SLA battery charger to see if there was any chance it would charge. It wouldn’t hurt to try. I left the battery connected to the charger for a couple of hours, but when I came back, the battery was still dead flat. Just as I was about to put the battery into the scrap pile again, I had a thought. I had nothing to lose, so I decided to connect my car battery charger to it. I came back after 15 minutes and the ammeter on the charger showed that the battery was charging. That was unexpected, but it was a good sign that the battery might be able to be salvaged. I didn’t want to leave the battery connected to the car battery charger, so I swapped it for my SLA charger, and the charger’s LED turned red, indicating that the battery was charging. After several hours of charging, I switched the charger off and got a 55W quartz halogen globe and tested the battery with it. The globe lit up at full brightness, showing that the SLA battery had come good. I had another old SLA battery in the scrap pile, so I thought I would try charging it with the car battery charger, but it did not work, no doubt due to the age of the battery. Also, it had bulging ends, indicating that the plates had deteriorated to the point of no return. An SLA battery is only worth a few cents as scrap, but siliconchip.com.au a replacement battery is around $40. So this experiment was worthwhile. Sometimes in a situation like this, with nothing to lose, it pays to experiment. You never know when things might turn out better than expected. Samsung monitor reptile removal I’ve had this Samsung SyncMaster 2253BW monitor for many years. Previously it was in use in my back shed where I used to do electronics repairs before I got my new electronics workshop finished last year. I used to work more on computers and monitors, but now I mostly work on laptops. A few years ago, I went to switch on the monitor and it tripped the safety switch. I unplugged it and put aside. I reset the safety switch, got another monitor, and continued doing what I had been doing at the time. I suspected that a gecko might have gotten inside the monitor and shorted out something on the power supply board. I had this happen to an Asus monitor a long time ago. In that case, the fuse had blown and some tracks were damaged from arcing, but I was able to repair it. This monitor is a bit tricky to disassemble. I started by unscrewing the stand/base, then I unclipped the front screen surround. This gave me access to the two screws that hold the stand stem on, so I could remove it. Then, with the monitor face down, I could remove the back shell. With the back off, I unplugged the front control cable. There is a metal screen to remove, plus four plugs for the high-voltage supply. I put some dots on them so I would know which one went where, as I thought this might be important. I now had the metal shell with the power supply board and the video board loose from the rest of the Items Covered This Month • A shopping list of repairs • Lights out on a receiver • Fixing the fan bearings in a gas heater Dave Thompson runs PC Anytime in Christchurch, NZ. Website: www.pcanytime.co.nz Email: dave<at>pcanytime.co.nz Cartoonist – Louis Decrevel Website: loueee.com Australia's electronics magazine July 2026  89 The garden lights at night and one of the working glass solar panels. monitor. And there I found what was left of the gecko. After removing the gecko and cleaning the board, I could not see any damage. There were no burnt tracks or any other signs of damage, but there was a small area on the back of the screen with a black mark where the high voltage had arced onto the gecko. Maybe the gecko shorted things in such a way as not to cause any actual damage. Here’s hoping! I placed the metal shell with the boards in it on the concrete floor, plugged in a power cable and switched it on. Nothing happened. There was no smoke or any other sign of anything being wrong. Maybe I got lucky with this one. I put the monitor back together loosely so I could test it before reassembly. With it facing up, I connected it to power and pressed the power button on the front screen surround. The screensaver came on, indicating that the monitor still worked. I reassembled the monitor and then took it into the house and connected to my Linux laptop with a VGA cable. I got a good picture, so the monitor had been restored to working order. This time I didn’t have to actually repair anything, just remove the cause of the safety switch being tripped. Good thing we have a safety switch! Garden light repairs We have 50 garden lights around features in the front of our house and on the side of our driveway. Some of these lights need maintenance from time to time. I usually check them every so often to see if there are any that aren’t lit when it gets dark. It had been a few months since I last checked them, and I found that 30 weren’t working. The most common reason they fail is 90 Silicon Chip that the rechargeable AAA cell needs to be replaced. This was the case with 27 of the non-working lights. I only had 21 rechargeable AAA cells in stock, so I had to order some more cells on eBay. I usually get 24 at a time so that I have a good supply on hand. Another point of failure is the YX8018, which is a specialised, low-voltage solar LED driver IC used primarily in solar-powered garden lights, lawn lamps and fairy lights. It is a single-chip solution that manages battery charging during the day and drives the LED at night, operating efficiently at the low voltages typically supplied by a single 1.25V NiMH rechargeable cell. As with the cells, I was able to obtain replacement YX8018 ICs on eBay. Another point of failure is the colour-changing LED, which I occasionally have to replace if one colour goes out. I was also able to obtain these on eBay. It’s not very often that I need to change one, though, as they last a long time. The final point of failure is the solar panel, which is a 40 × 40mm glass panel. If this fails, the garden light is not repairable, as I cannot find glass solar panels of that size anywhere. Similar plastic solar panels are available on eBay but they cost more than a replacement garden light, and in any case, plastic solar panels are lucky to last a year here in the Queensland sun. The glass panels can last 10 years or more. As for the other three garden lights that were not working, two had a failed solar panel and one had a failed YX8018 IC. In the case of either component failing, the light will either not work at all or be on all the time in bright light. To find out which, I disconnect the solar panel from the circuit board, set it under a bright light and connect my multimeter to the wires. These small solar panels deliver around 1.8V at 20-100mA to charge the AAA cell during the day. They produce voltage even out of direct sunlight. They comprise three individual cells that generate around 0.6V each. I replaced the two lights with failed solar panels and repaired the last with a new YX8018 IC. Whenever I buy a new garden light, I take out the AAA cell that comes in it and I replace it with the much better one from eBay as these cells keep the light lit for longer at night and also have a longer life expectancy. In the process of repairing the garden lights, I had to reseal some holes where the wires from the solar panel Australia's electronics magazine siliconchip.com.au Servicing Stories Wanted Do you have any good servicing stories that you would like to share in The Serviceman column in SILICON CHIP? If so, why not send those stories in to us? It doesn’t matter what the story is about as long as it’s in some way related to the electronics or electrical industries, to computers or even to cars and similar. 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. Left: the standing spotlight, which was rewired so that it had a longer cable, and did not need an extension cable. enter the light, as some were not sealed correctly, allowing water to enter the light. This resulted in a couple of battery connectors needing to be replaced; I used parts from old lights that had failed solar panels. In over 10 years, I have amassed 20 lights with failed solar panels. I also replaced two glass bodies, as the water had rusted the bottom screws, which caused the screws to expand and break the glass. Sometimes a light may get broken from another cause as well. Simple headphone repair My son brought me some headphones that had the cord ripped off. He pointed out that there was a tiny piece of red wire still attached to one speaker terminal so I’d know which wire went where. I got my 20W soldering iron out and plugged it in to heat up while I prepared the wires for the repair. The wires appeared to be cotton-covered, multi-core enamelled copper wire, so I used a lighter to burn off the cotton covering and the enamel at the end. I was then able to tin each wire, ready to solder them back to their respective terminals on the speaker. I carefully soldered each wire to the correct terminal and put the speaker back onto its bracket. This was an easy repair that only took me a few minutes. I gave the headphones back to my son and suggested that they should be stored where their cat could not find them again, as it was fortunate that the headphones had not been ripped to pieces. If the cat had another go at them, it could end up a lot worse than just the wires ripped off. Rewiring a standing spotlight I’ve had this standing spotlight for several years, but hadn’t used it. It had a short cable with a footswitch, which may have worked well inside a house with the power siliconchip.com.au points near the floor, but it was impractical in my workshops with power points above the benches. I had been using it with an extension cable, but I decided to rewire it to have a longer cable without the foot switch. I looked on Jaycar’s website and found the exact cable I needed, sold by the metre. I worked out that I needed six metres, as the stand was around 1.5m high and that would give me around 4.5m of cable to reach a nearby convenient power point. I knew I had a plug to suit this twin-core flat cable, as I had planned to use it to repair a fan from the local Tip Shop that someone had cut the plug off, but at the time I could not find it. In the meantime, I had found it and lost it again, but after a quick search, I located it and put it on my workbench until the cable arrived. When it did, I started by removing the two screws securing the shade and lamp holder to the stand. Then I fed some cable up through the stand so I had working room to disconnect the cable from the lamp holder. With that done, it was time to remove the old cable and run the new cable through the stand and connect it at both ends. After removing the lamp holder and the lampshade, I tried pulling the cable through the stand from the bottom, but it got stuck and I could not pull it through. I suspected that there might be a join in the cable, so I unscrewed the segments one-by-one and, sure enough, there was a join in the cable. I cut the joint off the cable and I was then able to extract the old cable through the segments and then through the bottom of the stand and out of the base, ready for the new cable to be installed. I fed the cable into the stand base from the bottom, Australia's electronics magazine July 2026  91 The JVC receiver, which needed tracks to be bypassed with wire, due to corrosion. disintegrate is a mystery because they are on opposite ends of the PCB. On close examination, it looks like the tracks have oxidised in numerous sections. There is no visual indication of burning or lifting as if it had occurred from overcurrent heat stress. Editor’s note: while those supply tracks carried an AC voltage, there would likely have been a small DC voltage. That, combined with moisture and acid from decaying insects, is likely to lead to electrolytic corrosion. The solder mask is porous and doesn’t prevent the copper tracks underneath from corroding away under these conditions. Paul James, Kanwal, NSW. Braemar gas heater fan bearing repair but I found there was a plastic sleeve at the top of each section that the cable was getting caught on. I fed the cable through from the top instead, which proved to be successful. I screwed the segments together and then onto the base as I fed the cable through. Having connected the lamp holder and reassembled it, I screwed the lamp holder and shade back onto the top flexible part of the stand. The last job was to wire up the plug. A regular plug is not suitable for this two-core flat cable because the cable hole in the outer section of the plug is too big, so it was lucky I still had this one that suited the cable. With the rewiring finished, I tested the spotlight, and it worked as expected. JVC RX 5032-VSL receiver repair I was asked if I could do anything about the lights on an amplifier/receiver so it could be used properly. The amplifier had no display and therefore couldn’t be readily controlled because there was no indication of volume settings, radio stations or any other functions. I completely dismantled the receiver and found that numerous insects had entered the casing and had died there or been scorched. On tracing the power supply circuit for the vacuum fluorescent display, it was clear that no power was getting to it at all. The AC voltage was coming out of the transformer at 5V but not getting to the ribbon cable pins that supply the display. Testing with a multimeter on the PCB track from the transformer and the pins showed an open circuit no matter where tested along the PCB track. The same thing was happening on both outputs from the transformer. The PCB track appeared to be a different colour from the others and was unstable. Further testing on the track revealed that it was all open-circuit. The PCB track had to be bypassed with some wire to get the transformer output voltage to the ribbon cable, maintaining the resistor in one leg of the supply. During this process, I obtained a circuit diagram that showed that the transformer was supposed to be supplying 15V AC, but all my measurements showed 5V AC and the display worked after bypassing the faulty tracks, so I guess that must be correct. Apparently, the circuit I found is incorrect or for a different version because the transformer pinouts were different as well. What really caused both of the supply tracks to 92 Silicon Chip When purchased and installed in 1982, our Braemar gas wall heater fan was equipped with plain bronze bush bearings. By 2021, not only had the bushes worn out, but the bush at the fan end of the motor had worn a shallow groove into the motor shaft. Because there is only about a 10 thou (~0.25mm) clearance between the rotor and stator, the wear caused the rotor to rub against the inside of the stator and emit a rhythmic scraping sound, which steadily grew louder. By the winter of 2022, the friction of the rotor against the stator became sufficient to prevent the rotor from spinning. Ball bearings should have been fitted when the motor was manufactured. Provided that they were a reasonably tight fit on the shaft, the ball race would rotate with the shaft, and there would have been no shaft wear. Clearly, something needed to be done, but what? Braemar stated that they had no spare parts, but for approximately $3000 they would provide and install a whole new heater. Needless to say, that was never going to happen for the sake of a couple of measly ¼-inch bearings. I explored other possible sources of new motors or rotors, but couldn’t find any with a sufficiently long shaft. The options then were: Australia's electronics magazine siliconchip.com.au 1. Find and fit a new shaft. Perhaps a length of ¼-inch (6.35mm) diameter silver steel rod or a drill blank would do the trick. 2. Manufacture a new shaft from a suitable length of hardened steel. 3. Purchase a replacement motor of suitable dimensions but with a short shaft, and extend it using a collar. 4. Fill the grooves on the existing shaft, perhaps by metal spraying. 5. Turn some new bushes from bronze bar or rod. 6. Fit ball bearings and fill the shaft grooves with epoxy resin. 7. Fit ball bearings and fill the shaft grooves with epoxy resin reinforced with fine steel filings. Such mixes are available commercially, but anyone with some scrap metal and a file can make their own (I once drove from Oslo to London after repairing a chewed-out rear axle spline in this manner). Option #6 seemed to be the least expensive and most expedient. Even though epoxy is a relatively soft material compared to steel or chrome, it wouldn’t be subjected to wear so long as the shaft and inner race rotated as one. Because option #6 was likely to involve a delay of several days while suitable bearings were delivered, I attempted a temporary fix using the existing bush bearings by filling the groove worn into the shaft with epoxy mixed with graphite. In theory, the graphite would provide a low-friction bearing surface while the epoxy held it in place. Unfortunately, the epoxy collapsed after about four days, bringing the fan to a halt once more. Curses! By the time the ball bearings arrived, I’d refilled the groove worn in the shaft with plain epoxy and, using nothing more than a fine file, reduced the filler to the same diameter as the shaft. Voilà! The bearing slid on neatly with a small interference fit. Moreover, the ball bearing width proved to be equal to that of the original bronze bushes, so the shaft position and end play were no different once the original spacer was installed on the shaft between the rotor and fan end bearing. Having measured the bearing outer diameter, I made ready to turn a suitable spacer ring to support it inside the motor housing. Then I had a brainwave. Had my old friend Ian not recently gifted me a box of various-sized O-rings? Maybe the box might yield a couple sized suitably for this purpose. Indeed, I found four. There was only space for one per bearing, leaving the possibility of the O rings migrating to the outer end of the bearings and releasing them. I needed some annulus-shaped packing spacers that would slip over the bearing yet fit inside the housing. After rummaging through my box of washers and finding nothing suitable, I decided to experiment by cutting some thin cardboard packing washers. After all, there was no more danger of the cardboard burning than of the wiring or plastic formers within the motor. I could always make metal versions later if this worked. Work it did, and wonderfully so. The fan is silent and rotates with a vigour as never before. Whereas we habitually ran it at the medium speed setting, we now use only the low speed setting. It has been running this way for a couple of years, and I’ve never needed to replace the O-rings or cardboard washers with anything more substantial. SC Ron, via email. siliconchip.com.au Australia's electronics magazine July 2026  93