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Thanks for your time. I really enjoyed making this kit some 30 years after I built my first Jacob’s ladder from Oatley Electronics (it used a blue CRT flyback transformer). I am still having fun to this day. (M. A., via email) ● We think Leo specified raising the coil from the metal lid using plastic drink bottle tops to provide distance from the case, preventing the high voltage from the high tension output from arcing back to the case. However, you have a point that the mounting screw contacts the case and is quite close to the output terminals. Ideally, that screw should be plastic or at least shorter. You could run the coil wiring up through holes in the lid instead of being looped around from the side of the box. Suitable cable glands or grommets would be required for the cable to pass through the enclosure lid. As for operating from a mains power supply, the 12V supply will have a lot of high voltage spikes imposed upon the DC level that will likely damage your power supply. Also, any arcing from the Jacobs ladder to the supply can severely damage the power supply circuitry, which is why we do not recommend powering the Jacob’s ladder with anything except a 12V battery. Building the original Wideband unit kit I noticed that Jaycar still has Wideband Fuel Mixture Controller Kits (KC5486), but only via their website. The actual sensor can be picked up for around $40. I believe I would need the other kit, KC5485, to use the KC5486 kit. KC5485 is the display part of the system that gives you the information used to adjust the mixture in the carburettor to get the correct air:fuel ratio. I want to build both kits and connect the sensor in a tuning scenario for my 1960s, 1970s and 1980s A and A+ engines. Are all the bits to build the KC5485 kit still available, or can I get anything else to plug into the KC5486 to make it all work? Back in the day, I built many of your kits. I also once worked for George Brown and Co selling electronics at Parramatta Rd, Camperdown in Sydney. (S. C., Glenwood, Qld) Advertising Index Altronics.................................33-36 Dave Thompson........................ 111 Digi-Key Electronics...................... 3 Emona Instruments.................. IBC Hare & Forbes..........................OBC Jaycar................... IFC, 9, 12-13, 25, Keith Rippon Kit Assembly....... 111 Lazer Security........................... 111 LD Electronics........................... 111 LEDsales................................... 111 Microchip Technology.................. 7 Mouser Electronics....................... 4 Oatley Electronics..................... 111 Silicon Chip PDFs on USB....... 109 Silicon Chip Shop............ 104-105 Silicon Chip Subscriptions........ 37 Silicon Chip Test Tweezers..... 107 The Loudspeaker Kit.com............ 6 Tronixlabs.................................. 111 Wagner Electronics..................... 11 112 Silicon Chip Notes and Errata ..................................94-95, 99, 101 ● You can still build the original Wideband unit we designed in 2009 (siliconchip.au/Series/41), which the Jaycar kit is based on. It uses the older (but still available) Bosch LSU 4.2 wideband sensor. However, you might want to look at our new Wideband Fuel Mixture Display (WFMD) that uses the newer LSU 4.9 sensor, that started in the April 2023 issue (siliconchip.au/ Series/398), and finishes in this issue. It has other advantages: the controller is more compact, with extra features like Bluetooth connectivity. The Hand Controller is not required for the new design. We also have a short-form kit for building it. If you still want to build the 2009 design, you need the PCB and programmed microcontroller for the Display Unit. While this display PCB is from a later article, it is compatible with the 2009 design: siliconchip.au/ Shop/8/666 The programmed microcontroller is here: siliconchip.au/Shop/9/1161 Jaycar still sells the 7-segment displays (ZD1857), and you should be able to source the most of the other SC parts from Jaycar. Automated Test Bench Swiss Army Knife, April 2023: 1. the lid cutting diagram, Fig.2 on p64, has the vertical location of the rectangular cut-out too low. The top of the cut-out should be in line with the centres of the upper holes marked “A”, not 5mm below that line. While not critical, it could also be moved 1mm to the right. 2. In the production of the original (Rev A) PCBs, one row of pins (20 to 38) on the ESP32 socket was reversed. Rev B boards are not affected. Rewiring pins 20-38 of the socket is the most straightforward means of rectifying the problem. Please contact us for instructions if you have one of the original PCBs Advanced SMD Test Tweezers, February & March 2023: the Fig.1 circuit diagram (p46, February) labels pins 24 and 25 of IC1 as AN11 and AN10 instead of AN7 and AN6. AM-FM DDS Signal Generator, May 2022: the gate bias for Mosfet Q1 is fixed at 1.5V. Since the threshold of Q1 can range from 1.0V to 2.5V, that might not suit all 2N7002 devices. If there is no output from IC3, the bias might be too low, in which case the 3.3kW resistor can be changed to 4.7kW (1.8V) or 6.2kW (2.0V). If there is output from IC3, but the modulation is weak, the bias might be too high, in which case the 3.3kW resistor can be changed to 1.8kW (1.05V). Advanced GPS Computer, June and July 2021: the circuit diagram (Fig.1, p27, June) and overlay diagram (Fig.2, p78, July) label the data line from the GPS module as RX. It was not mentioned explicitly in the text that this should connect to the TX wire of the GPS module. For the suggested module, the pins/wires labelled E (yellow), G (black), T (blue) and V (red) go to the GPS1 pads EN, G, RX and 5V on the PCB, respectively. The other two are not needed and can be soldered to the remaining GPS1 pads. Next Issue: the July 2023 issue is due on sale in newsagents by Thursday, June 29th. Expect postal delivery of subscription copies in Australia between June 28th and July 14th. Australia's electronics magazine siliconchip.com.au