bench power supply

11 Articles

Repairing A BPS-305 30V Bench Power Supply

December 31, 2024 by 6 Comments

When [Tahmid Mahbub] recently reached for his ‘Lavolta’ BPS-305 bench supply, he was dismayed to find that despite it being a 30V, 5A-rated unit, the supply refused to output more than 15V. To be fair, he wasn’t sure that he had ever tried to push it beyond 15V in the years that he had owned it, but it had better live up to its specs. Ergo out came the screwdriver to open the power supply to see what had broken, and hopefully to fix it.

After some more probing around, he discovered that the unit had many more issues, including a highly unstable output voltage and output current measurement was completely wrong. Fortunately this bench power supply turns out to be very much like any number of similar 30V, 5A units, with repair videos and schematics available.

While [Tahmid] doesn’t detail his troubleshooting process, he does mention the culprits: two broken potentiometers (VR104 and VR102). VR104 is a 5 kOhm pot in the output voltage feedback circuit and VR102 (500 Ohm) sets the maximum output current. With no 500 Ohm pot at hand, a 5 kOhm one was combined with a 470 Ohm resistor to still allow for trimming. Also adjusted were the voltage and current trimpots for the front display as they were quite a bit off. Following some testing on the reassembled unit, this power supply is now back in service, for the cost of two potentiometers and a bit of time.

A Very Tidy ATX Bench PSU

December 8, 2022 by 20 Comments

If there’s one thing that for decades of desktop PCs have given us, it’s a seemingly endless supply of relatively capable power supplies. If you need 5 volts or 12 volts at a respectable current they’re extremely useful, so quite a few people have used them as bench power supplies. Some of these builds box up the mess of wires into a set of more useful connectors, but [Joao Pinheiro] has taken his to the next level with a very neat 3D printed case and a set of variable switching regulators to make a variable bench supply with a top voltage of 60 volts.

In many ways it’s a straightforward wiring job to build, but there’s an unexpected power resistor involved. It’s sinking the 5 volt line, and we’re guessing that some current is required here for the PC power supply to run reliably. The thought of a high power resistor dumping heat into a 3D printed case leads us to expect that things might become a little melty though.

ATX power supplies are so numerous as to be expendable, so it’s always worth regarding them as a source of parts as well as a power supply.

A Particularly Polished ATX Bench Power Supply

August 18, 2022 by 43 Comments

Let’s be real, yanking the ATX power supply out of an old desktop computer and turning it into something you can use on the workbench isn’t exactly an advanced project. In fact, you could probably argue it’s one of the first DIY builds a budding electronic hobbyist should tackle — after all, you’re going to need a reliable bench supply if you want to do any serious work anyway.

But of course, there’s a big difference between doing the minimum and really giving something your all, and we think this ATX bench supply from [Steve Thone] of The Neverending Projects List is a phenomenal example of the latter. It not only looks impressive, but it’s been tricked out with plenty of bells and whistles to make it as capable as possible. What was once a basic 230 watt PSU pulled from an old Dell is now a piece of gear that any hacker or maker would love to have in their collection. Continue reading “A Particularly Polished ATX Bench Power Supply” →

DIY Bench PSU Looks Like A Million Bucks But Is Easy On The Budget

April 27, 2022 by 29 Comments

As one becomes more and more involved in hobbies that involve electronics of almost any kind, it becomes necessary to graduate from wall warts and USB power breakout boards and move up to something more substantial. One great way to do this is to repurpose an old computer PSU, and that’s exactly what the excellent writeup by [Mukesh Sankhla] shows us how to do.

Starting with an ATX power supply from a derelict computer that was otherwise heading to to the bin, [Mukesh] walks us through the teardown of the power supply as well as how we can rebuild it in a snazzy 3d printed case complete with a voltage readout.

Now it’s easy to say “Sure, this is just another ATX PSU project” but the care that went into making a nice case adds a lot to build. There’s another element that is extremely important: The power resistor across the 5 Volt power bus. There are cheap kits online that will break out an ATX PSU into banana plugs, but they omit this vital piece. Depending on the ATX power supply being used, they may be unstable without the load.

The project also leaves a lot of room for adding your own hacks such as variable voltage and current limiting. We think this PSU would be a great (and great looking) addition to any hacker’s workbench. If ATX Power Supply get your electrons flowing, check out this entire computer built into a gutted ATX PSU.

Printed Jig Is A Welding Rig

May 13, 2020 by 17 Comments

[NixieGuy] was scheming to build robots with cable-driven joints when the pandemic hit. Now that component sourcing is scarce, he’s had to get creative when it comes to continuous cables. These cables need to be as seamless as possible to avoid getting caught on the pulleys, so [Nixie] came up with a way to weld together something he already has on hand — lengths of .45mm steel cable.

The 3D printed jig is designed to be used under a digital microscope, and even clamps to the pillar with screws. Another set of screws holds the two wires in place while they are butt welded between two pieces of copper.

[Nixie] adds a spot of solder paste for good measure, and then joins the wires by attaching his bench power supply set to 20V @ 3.5A to the copper electrodes. We love that [Nixie] took the time to streamline the jig design, because it looks great.

This just goes to show you that great things can happen with limited resources and a little bit of imagination. [Nixie] not only solved his own supply chain problem, he perfected a skill at the same time. If you don’t have a bench supply, you might be able to get away with a battery-powered spot welder, depending on your application.

A USB-C Bench Power Supply

November 4, 2019 by 8 Comments

A bench power supply is one of those things that every hacker needs, and as the name implies, it’s intended to occupy a place of honor on your workbench. But with the addition of USB-C support to his DPH5005 bench supply, [Dennis Schneider] is ready to take his on the road should the need ever arise.

The build started with one of the common DPH5005 bench power supply kits, which [Dennis] says he was fairly happy with aside from a few issues which he details in the post on his blog. Even if you aren’t looking to modify your own kit with the latest and greatest in the world of Universal Serial Bus technology, it’s interesting to read his thoughts on the power supply kit if you’ve been considering picking one up yourself.

Under normal circumstances you are supposed to give the DPH5005 DC power via the terminals on the back panel of the supply, which in turn is regulated and adjusted via the front panel controls. To add support for USB-C, all [Dennis] had to do was install a USB-PD trigger module configured to negotiate 20 VDC in the back of the case and connect it to the DC input. To hold it in place while isolating it from the metal case, he used a piece of scrap PCB carefully cut and wrapped in Kapton tape.

This actually isn’t the first portable bench power supply we’ve seen. Last year we saw one that got its input power from Makita portable tool batteries, but we think all things considered, the USB-C option is probably a bit more convenient.

Bench Power Supply Packs A Lot Into A DIN-Rail Package

August 18, 2018 by 8 Comments

We’re not sure why we’ve got a thing for DIN-rail mounted projects, but we do. Perhaps it’s because we’ve seen so many cool industrial control cabinets, or maybe the forced neatness of DIN-mounted components resonates on some deep level. Whatever it is, if it’s DIN-rail mounted, chances are good that we’ll like it.

Take this DIN-mounted bench power supply, for instance. On the face of it, [TD-er]’s project is yet another bench supply built around those ubiquitous DPS switching power supply modules, the ones with the colorful displays. Simply throwing one of those in a DIN-mount enclosure isn’t much to write home about, but there’s more to this project than that. [TD-er] needed some fixed voltages in addition to the adjustable output, so a multi-voltage DC-DC converter board was included inside the case as well. The supply has 3.3, 5, and 12 volt fixed outputs along with the adjustable supply, and thanks to an enclosed Bluetooth module, the whole thing can be controlled from his phone. Plus it fits nicely in a compact work area, which is a nice feature.

We haven’t seen a lot of DIN-rail love around these pages — just this recent rotary phase converter with very tidy DIN-mounted controls. That’s a shame, we’d love to see more.