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MARKET CENTRE Advertise your product or services here in Silicon Chip KIT ASSEMBLY & REPAIR FOR SALE PCB PRODUCTION DAVE THOMPSON (the Serviceman from Silicon Chip) is available to help you with kit assembly, project troubleshooting, general electronics and custom design work. No job too small. Based in Christchurch, New Zealand, but service available Australia/NZ wide. Email dave<at>davethompson.co.nz LEDsales PCB MANUFACTURE: single to multilayer. Bare board tested. One-offs to any quantity. 48 hour service. Artwork design. Excellent prices. Check out our specials: www.ldelectronics.com.au KEITH RIPPON KIT ASSEMBLY & REPAIR: * Australia & New Zealand; * Small production runs. Phone Keith: 0409 662 794 keith.rippon<at>gmail.com LEDS, BRAND NAME AND GENERIC LEDs, filament LEDs, LED drivers, heatsinks, power supplies, kits and modules, components, breadboards, hardware, magnets. Please visit www.ledsales.com.au Silicon Chip Binders REAL VALUE AT $21.50 PLU S P&P PMD WAY offers (almost) everything for the electronics enthusiast – with full warranty, technical support and free delivery worldwide. Visit pmdway.com to get started. Order online from www.siliconchip. com.au/Shop/4 or call (02) 9939 3295. ADVERTISING IN MARKET CENTRE Classified Ad Rates: $32.00 for up to 20 words (punctuation not charged) plus $1.20 for each additional word. Display ads in Market Centre (minimum 2cm deep, maximum 10cm deep): $82.50 per column centimetre per insertion. All prices include GST. Closing date: 5 weeks prior to month of sale. To book, email the text to silicon<at>siliconchip.com.au and include your name, address & credit card details, or phone (02) 9939 3295. (https://github.com/esp8266/Arduino/ releases/tag/3.0.0). The quickest fix will be to change the installed version of the board profile from the Boards Manager (there is a drop-down to change the version). We don’t have a record of the version used for the original project, but it was likely one of the later 2.x.x versions. We suggest you try 2.7.4. There were similar problems with the Clayton’s GPS Time Source project and version 2.7.4 worked in that case. Wideband Differential Probe output is too high I’ve finally got around to building the Wideband Active Differential Probe (from the September 2014 issue; siliconchip.au/Article/7995). I ordered the parts in 2015, lost them, then finally ordered them again a couple of months ago... siliconchip.com.au I realise that this is an old project. However, I wondered if you might have any troubleshooting information available based on any questions at the time. I’ve looked in my old magazines for the couple of months after in case there was anything there, but didn’t find anything. My problem is that when feeding in a 2V peak-to-peak square wave at around 200kHz, the voltages displayed on the oscilloscope are either 3.32V peak-to-peak at ×1 or an overshooting 3.6V peak-to-peak (3.2V if I ignore the overshoots) at ×10. The overshooting looks much like the shape of needing to calibrate a probe. The connection to the oscilloscope is an SMA-to-BNC coaxial cable and I’m feeding the probe’s inputs from the 50W output of a signal generator via a BNC to crocodile clip coaxial cable. I’ve measured the output of the signal generator using its 600W output direct Australia's electronics magazine to the scope with a BNC-BNC coaxial cable and this matches the 2V peak-topeak the generator claims to put out. Any troubleshooting thoughts, hints or pointers would be much appreciated. (J. B., Little River, New Zealand) ● The Wideband Active Differential Probe is designed to be used with a 50W cable to the oscilloscope and with 50W termination. Without this, the displayed levels will be incorrect. Many oscilloscopes have a 50W termination option for each input. Make sure you’ve enabled it for the one the Probe is connected to. If you are using this 50W termination, perhaps the gain of the differential amplifier is not correct. Check the values of the 1kW and 1.3kW resistors that set the gains of IC1 and IC2. Also check that the three 3MW resistors in series at the input and the 1MW shunt resistors at the gates of Q1 and Q2 are correct. April 2025  103