EEVblog

The Uni-T UDP6700 series UDP6731 360W slimline Bench Lab Power Supply REVIEWED https://instruments.uni-trend.com/products/dc-power-supplies/UDP6700 https://uni-trendus.com/products/udp6731-360w-basic-dc-switching-power-supply-80v-15a 00:00 – Uni-T UDP6731 PSU 01:30 – Beware of thermal stacking 02:55 – Teardown 07:35 – Sneaky fan 11:24 – Remember the Riden RD6006, also 350W 13:10 – Power up 16:04 – The display and UI 18:14 – Instantaneous knob 19:16 …

More Mailbag! 00:00 – Zifnu K-16 Kickstarter LED light https://www.zifnu.com/ 11:02 – Qoool Sensing: Diamond Quantum Fluorescence Demo https://qoool-sensing.org 16:41 – Logic Gate Educational Demo Board https://logicgat.es/ 20:15 – Beelink ME Mini 6 x M.2 Slot Home Storage NAS https://www.bee-link.com/products/beelink-me-mini-n150?ref=OKJKQ Forum: https://www.eevblog.com/forum/blog/eevblog-1690-mailbag-zifnu-led-quantum-diamonds-logic-gates-m-2-nas/

Another Colour A3 photocopier in the dumpster! Is this an upgrade? Fuji-Xerox Docucentre V C4476 Forum: https://www.eevblog.com/forum/blog/eevblog-1689-another-dumpster-diving-a3-colour-photocopier/

DC Constant Current sources explained and demonstrated. Forum: https://www.eevblog.com/forum/blog/eevblog-1688-constant-current-sources-explained-demo/ Voltage and Current Source Theory: https://www.youtube.com/watch?v=AQK7RyecVW0 DC Circuit Fundamentals Playist: https://www.youtube.com/playlist?list=PLvOlSehNtuHtVLq2MDPIz82BWMIZcuwhK 00:00 – Constant Current Sources 11:08 – Practical uses of constant current sources 14:00 – Circuit examples 19:13 – TL431 Example 20:25 – LM317 CC circuit 21:42 – Low Side Source vs High Side Current …

The repair of alkaline battery leakage in this Keysight U1177A Bluetooth mulitmeter adapter was, well, pointless…. Forum: https://www.eevblog.com/forum/blog/eevblog-1687-a-pointless-alkaline-battery-leakage-repair-462018/

A complete walkaround of the Electronex 2025 exhibition in Melbourne Forum: https://www.eevblog.com/forum/blog/eevblog-1686-electronex-2025-melbourne-walkaround/

A walk around the Australian Manufacturing Week exhibition in Melbourne 2025, looking at mechanical stuff Dave has no idea about. Forum: https://www.eevblog.com/forum/blog/eevblog-1685-australian-manufacturing-week-2025-walkaround/

Test Controller is an awesome free logging and control software that supports a ton of multimeters, power supplies and loads, including the new BM2257. https://lygte-info.dk/project/TestControllerIntro%20UK.html https://lygte-info.dk Forum: https://www.eevblog.com/forum/testgear/program-that-can-log-from-many-multimeters/

Sun-Ways actually went ahead and installed Solar Freakin' RAILways in the Swiss village of Buttes at the cost of US$700,000 ! References: https://www.swissinfo.ch/eng/climate-change/switzerland-turns-train-tracks-into-solar-power-plants/89227914 https://www.swissinfo.ch/eng/science/swiss-solar-railway-project-gets-back-on-track/87707181 https://www.startupticker.ch/en/news/sun-ways-opens-world-s-first-rail-ready-track-mounted-solar-power-plant https://www.youtube.com/@sun-ways https://www.pv-magazine.com/2024/04/09/italian-startup-testing-pv-sleepers-on-railway-line/ https://pvwatts.nrel.gov/pvwatts.php Paper on railway dust: https://www.sciencedirect.com/science/article/pii/S004896971401451X?via%3Dihub https://pubmed.ncbi.nlm.nih.gov/25461038/ Forum: https://www.eevblog.com/forum/blog/eevblog-1683-sun-ways-solar-freakin-railways-part-2/ Part 1: https://www.youtube.com/watch?v=7vItnxhWRqw

One of my 14 Enphase microinverters failed and they sent me a new one under warranty, lets install it… Forum: https://www.eevblog.com/forum/blog/eevblog-1682-enphase-microinverter-fail-warranty-install/

More mailbag! 00:00 – A really really nice DIY Constant Current Load 07:55 – Whatever happened to sloped folded metal instrument cases? 08:46 – The amazing Stamp Breadboard Replacement prototype boards (Link coming soon) 13:35 – A look at the Stamp documentation 21:14 – Ian Scott Johnston's Multimeter Continuity Speed Tester! https://www.youtube.com/@UCtiK8QrcCrsjDXpKzB1PO1A https://www.ianjohnston.com/ Forum: https://www.eevblog.com/forum/blog/eevblog-1681-mailbag-nice-diy-cc-load-amazing-proto-boards-ian-johnston/

New research shows you can extract a tiny voltage and current from a stationary tube in the earth's magnetic field. Is this real? It is scaleable to be useful? Paper: https://journals.aps.org/prresearch/abstract/10.1103/PhysRevResearch.7.013285 IEEE article: https://spectrum.ieee.org/decarbonized-future Forum: https://www.eevblog.com/forum/blog/eevblog-1680-free-energy-from-the-earths-magnetic-field/

Why does the Uni-T UTG9504T abitary function generator cost US$5800? A teardown and detailed BOM cost analysis of how much high end product designs costs, and the margins involved. Forum: https://www.eevblog.com/forum/blog/eevblog-1679-why-does-this-uni-t-awg-cost-$5800-bom-cost-analysis-458562/ 00:00 – Why does this Arbitrary Waveform Generator cost US$5800 ? 02:17 – 2.5x BOM Cost multiplier 03:02 – Teardown 06:02 – Power Supply …

53 minutes single take randomly walking the streets of Sydney with Mehdi from ElectroBOOM. That is all. Forum: https://www.eevblog.com/forum/blog/electroboom-stalks-sydney/

Oscilloscope have a pre-arm trigger period that can cause confusion if you aren't aware of it. And how different scopes operate and indicate this in different ways. Also some potential bugs in the Keysight 3000 and HD3 series scopes. 00:00 – Slow timebases can be problematic for triggering 02:13 – What happens when you press …

An experiment to test an interesting effect with fuses. Forum: https://www.eevblog.com/forum/blog/eevblog-1677-an-interesting-effect-with-fuses-(experiment)/

Modifying a lab timer to automatically trigger when a fuses blows, for automated fuse testing. Fuses video: https://www.youtube.com/watch?v=WG11rVcMOnY Jellybean Transistors: https://www.youtube.com/watch?v=XYdmX8w8xwI Forum: https://www.eevblog.com/forum/blog/eevblog-1676-lab-timer-hack/

Our Ninja blender blade failed. For a warranty replacement they wanted us to DESTROY and DISPOSE OF the old perfectly working base unit before sending a new one. Let's see about that… The first ever EEVBlog video with zero commentary, just memes. My breakfast smoothie: https://www.youtube.com/shorts/-2mf1mqZVQ0 Forum: https://www.eevblog.com/forum/blog/eevblog-1675-ninja-blender-repair-because-why-(right-to-repair)/ Credits: “Our Story Begins” Kevin MacLeod (incompetech.com) …

A big dumpster diving find! What did Dave score this time?

A quick follow-up to the JBL Partybox 310 speaker repair and speculation on WHY the fault happened the way it happened. Contains SPOLIERS, so watch Part 1 first! Forum: https://www.eevblog.com/forum/blog/eevblog-1672-jbl-repair-youll-never-guess-the-fault/

Repair of a JBL Partybox 310 speaker. Follow along as Dave goes down the repair rabbit hole. Try and guess the exact fault before Dave does, it's a doozy! 00:00 – JBL Partybox 310 Speaker fault symptoms and initial failure speculation 02:57 – Teardown 06:23 – Is it a firmware lockup issue? 07:17 – Checking …

How can the same sh!t happen to the same guy twice? And a trap for young players with LCD's. And a giveaway for the young whippersnapper in Australia. Forum: https://www.eevblog.com/forum/blog/eevblog-1670-bm786-multimeter-battery-leakage-repair-giveaway/ 00:00 – How can the same sh!t happen to the same guy twice? 06:27 – Zebra strip elastomeric connector 09:40 – It STILL doesn't work? …

A mailbag replacement custom LED display for the Agilent U53131A VFD display frequency counter. www.hubequip.net Forum: https://www.eevblog.com/forum/blog/eevblog-1669-agilent-u53131a-vfd-to-led-display-upgrade-mailbag/

Horrific alkaline battery leakage in a rare prototype EEVblog 555 Multimeter. Can it be repaired? Forum: https://www.eevblog.com/forum/blog/eevblog-1668-horrific-alkaline-battery-leakage-in-rare-prototype-multimeter/

Reverse Engineering the Brymen BM2257 Multimeter front end to understand what changes have been made from the BM235 in the Low Z mode. DaveCAD time. Also some testing of the LowZ mode and how it works. Forum: https://www.eevblog.com/forum/blog/eevblog-1667-reverse-engineering-the-brymen-bm2257-multimeter/ MOV datasheet: https://www.cnr.com.tw/cloudSpace/CNR_D.pdf How to reverse engineer: https://www.youtube.com/watch?v=lJVrTV_BeGg Multimeter Input Protection: https://www.youtube.com/watch?v=zUhnGp5vh60

Let's find out what this blown SMD part is, sent in by a viewer. Forum: https://www.eevblog.com/forum/blog/eevblog-1666-blown-smd-component-identification/ Component Playlist: https://www.youtube.com/playlist?list=PLvOlSehNtuHtdQF-m5UFZ5GEjABadI3kI

Part 2 of the Keithley 2302 battery simulator repair of the VFD display. Just a follow-up on testing the actual VFD display itself to see if there is any fault that's not the VFD vacuum. 00:00 – Having another look at the failed Newhaven VFD dispaly module 05:37 – Measurign voltages 07:32 – Oscilloscope probing …

Repair of a Keithley 2302 battery simulator with junk bin parts. But it did put up a fight! Teardown video: https://www.youtube.com/watch?v=5LK8wduZsy0 Forum: https://www.eevblog.com/forum/blog/eevblog-1664-repair-with-junk-bin-parts!-keithley-2302/ 00:00 – Faulty VFD display in a Keithley 2302 Battery Simulator 01:22 – Teardown 03:14 – The Display driver PCB 04:30 – Solder Sucking Sucks 05:26 – The VFD display module, a …

Repairing a customers Brymen BM786 multimeter, and investigating the cause of the InEr error message on the input jack alert feature. Plus a giveaway to a local youngster. 00:00 – A returned BM786 Multimeter with InEr error message 03:23 – Split jacks and input alert circuit 05:19 – In-Circuit probing TIP and Low Ohms mode. …

This was going to be a repair of a vintage Tandy 200 Portable Computer… Forum: https://www.eevblog.com/forum/blog/eevblog-1662-vintage-tandy-200-portable-computer-claytons-repairteardown/ 00:00 – I sear this Tandy 200 had a problem… 02:54 – Teardown 03:57 – The new BM2257 Multimeter 05:25 – I think it's the buzzer 08:06 – Microscope teardown 16:20 – They don't make service manuals like they …

The difference between Time Domain and Frequency Domain in AC circuit analysis. AC Theory Playlist: https://www.youtube.com/playlist?list=PLvOlSehNtuHvD6M_7WeN071OVsZFE0_q- Forum: https://www.eevblog.com/forum/blog/eevblog-1661-ac-basics-tutorial-part-5-time-domain-vs-frequency-domain/

Part 4 in the AC basics tutorial series. AC applied to resistors, capacitors and inductors, along with Capacitive Reactance and Inductive reactance. AC Theory Playlist

Review of the new Quick 861 Pro hot air station compared to the original 861DW. Forum: https://www.eevblog.com/forum/blog/eevblog-1659-quick-861-pro-hot-air-station-review/

It's important to understand the difference between Mean and Median, not just for engineering, but for everyday life, so you don't get manipulated by people with bad intentions. UBS Global Wealth Report: https://www.ubs.com/content/dam/assets/wm/global/insights/doc/global-wealth-report.pdf Forum: https://www.eevblog.com/forum/blog/eevblog-1658-tutorial-mean-vs-median/

Almost 30 minutes of tearing down a Samsung 75″ QLED One Connect dumpster TV and trying to power it up to see if it's busted or not. QA75Q7FNA 00:00 Dumpster Samsung QLED 75″ 04:46 – Teardown wasn't easy as expected… 08:11 – What is this cable retention BS? 11:26 – I'm still at it… 14:22 …

More Mailbag! 00:00 – DPS Ultrathin DIN 5V PSU's https://digitalpowersystems.eu/de/standard-produkte/ 01:15 – The Knife 06:16 – USB-C Isolator https://digitalpowersystems.eu/de/schnelle-und-sichere-usb-zu-uart-kommunikation-dank-digitaler-isolierung-und-esd-schutz-fur-ein-und-ausgange/ 07:34 – Zubax FluxGrip FG40 Electropermanent Magnet for Drones https://zubax.com/products/magnets/fluxgrip/fg40 11:55 – Testing the magnet 14:04 – Drone delivered multimeters? 14:53 – Why did someone send this? 15:46 – Wireless Freakin' Road Charging https://www.youtube.com/watch?v=sisD61ohzK0 19:37 – …

You can use almost any decent modern multimeter to safely discharge high voltage capacitor banks WITHOUT a LowZ function. Forum: https://www.eevblog.com/forum/blog/eevblog-1655-multimeter-tip-discharge-capacitors-using-any-meter/ Transistor Zener Clamp video: https://www.youtube.com/watch?v=BGcKjy_UNQ4

A full 3 hour discussion with the legendary Lee Felsenstein, designer of the Osborne 1, SOL computer, VDM-1, Pennywhistle modem, and the inventor of social media. Covering everything from the Berkeley free speech movement, the counterculture movement, his career, through to Obsorne and how he invented social media with Community Memory. His book: https://www.amazon.com/Me-My-Big-Ideas-Counterculture/dp/B0DJ8T45F1/ https://felsensigns.com/ …

Revisiting the alkaline battery leakage testing with a 555 circuit from a viewer. Forum: https://www.eevblog.com/forum/blog/eevblog-1653-alkaline-battery-leakage-testing-2-electric-boogaloo/ Final results of the first leakage testing: https://www.youtube.com/watch?v=BScnU4BT4xk

Why is my lab power switchboard wired like this? Forum: https://www.eevblog.com/forum/blog/eevblog-1652-why-is-my-lab-switchboard-wired-like-this/

I'm finally upgrading the infamous rats nest home switchboard! https://insightelectrical.com.au/ Forum: https://www.eevblog.com/forum/blog/eevblog-1651-home-electrical-switchboard-upgrade/ 00:00 – A look at the old switchboard 03:29 – Single Phase 04:57 – Surge protection 05:28 – Old school ceramic fuses 06:04 – Inside the infamous Rats Nest! 08:29 – Simon from Insight Electrical 09:09 – Could you still do wiring like …

Review of the Sequre HT-140 USB-C Desoldering Tweezers https://sequremall.com/collections/diy-tools/products/sequre-ht140-2in1-hot-tweezers-soldering-iron-desoldering-repair-tool-for-smd?variant=44204748275900 Forum: https://www.eevblog.com/forum/blog/eevblog-1650-sequre-ht-140-smd-desoldering-tweezers-review/

More mailbag! 00:00 – Everyones favourite segment! 01:00 – The very clever Edge Wedge from Metric Mind – Zero footprint programing header https://metricmind.com/ 05:19 – M5Stack Embedded processor modules https://shop.m5stack.com/products/m5stack-core2-esp32-iot-development-kit 11:28 – Err, the polarity is BACKWARDS! 12:41 – The M5stack website and UIflow2 GUI software 21:20 – Teardown of the M5stack Core2 module 23:16 …

USB Battery bank charger capacity explained. When you are comparing battery banks you want to use a measured Output Referred capacity figure, not an Input Referred mAh or Wh figure the manufacturers marketing department gives you. Forum: https://www.eevblog.com/forum/blog/eevblog-1648-input-vs-output-referred-battery-capacity-explained/

You might have thought the Rouute road based energy system was gone, but like a phoenix it has returned from the grifting ashes as R-2ENERGY! Sadly, Discount Morgan Freeman has been replaced by discount Joe Average https://www.r-2e.com/ https://find-and-update.company-information.service.gov.uk/company/11768960 https://www.linkedin.com/company/r-2energy/ Forum: https://www.eevblog.com/forum/blog/eevblog-1647-road-based-energy-again-rouute-vs-r-2energy/ The original video has the full debunk on why this is fundamentally a stupid …

FixHub portable soldering station REVIEW https://www.ifixit.com/products/fixhub-power-series-portable-soldering-station Just the iron: https://www.ifixit.com/products/fixhub-power-series-smart-soldering-iron Schematic: https://www.ifixit.com/Document/MeQmLlLKT2LSSKFY/Portable-Power-Station-Electrical-Schematics.pdf Repair Guide: https://www.ifixit.com/Device/FixHub_Portable_Power_Station 3D Model: https://www.printables.com/model/1018125-fixhub-power-series-portable-power-station/ How intercreate designed the FixHub: https://www.intercreate.io/case-stories/ifixit-soldering-iron-and-smart-hub 00:00 – iFixIt FixHub Portable Soldering Station 01:26 – iFixit Screwdriver set + unboxing 02:41 – The smart iron 03:41 – The Portable Power hub 05:04 – The smart iron in …

Is the US$80 Quick TS11 80W Soldering station any good? SPOILER: Nope, it's pretty terrible. Forum: https://www.eevblog.com/forum/blog/eevblog-1645-$80-quick-ts11-soldering-station-review/

More mailbag! 00:00 – Crowview Monitor & Keyboard https://www.elecrow.com/crowview-note-all-in-one-portable-monitor-phone-to-laptop-device-with-full-featured-type-c-sbcs-mini-pc-pc-game-console-compatibility.html 08:11 – Casio Border Army Game+Watch 11:34 – Minipa ET-1700 Pocket Multimeter 13:24 – Adafruit PCB Ruler 14:14 – PASS Card Game 15:13 – Crusty Raspberry Pi 17:40 – Sinusoid 4-20mA Rotary Encoder 29:29 – Wurkkos H1 USB Battery Bank 36:05 – Rulerize, transparent ruler sticker …

You get what you pay for in EV chargers. Don't buy this super cheap New Energy brand 7kW 32A EVSE Charger. Does it even meet the IEC 62752 it claims on the label? Or the US UL 2231 standard? MIDA brand EVSE: https://www.youtube.com/watch?v=SrZgN_EuRGw

Can I resurrect my first digital multimeter? A Soar ME-533 Forum: https://www.eevblog.com/forum/blog/eevblog-1641-can-i-resurrect-my-first-digital-multimeter/ 00:00 – My first digital and analog multimeters, Soar ME-533 + Micronta 22-201U 03:20 – Battery terminal corrosion, of course 05:13 – My first pair of pliers and screwdriver 06:11 – Teardown 08:10 – Removing the LCD 10:24 – LCD under the microscope, …

How DC Solar Isolators Work (TEARDOWN) 00:00 – Teardown of Benedict LS25 Solar True DC Isolator Switch 04:29 – How the contacts work 06:02 – How arc chutes and arc barriers work 12:11 – 5000V arc testing Datasheet: https://www.benedict.at/files/documents/6617533-DC-Switch-Disconnector-D946E.pdf Forum: https://www.eevblog.com/forum/blog/eevblog-1641-how-dc-solar-isolators-work-(teardown)/