Electrical issues ?
Electrical issues ?
The label indicates 650VA and 390W, which means it offers ample power for your AMD FM2 desktop or laptop. It could even handle running the system, monitor, and laptop at the same time.
I own a few outdated 650VA/350W Belkin UPS units that I still use for non-essential devices; they remain functional after almost 15 years, despite several battery replacements.
The uncertainty remains whether your device produces a square wave, a smoothed sine wave, or a pure sine wave. If it’s a clean sine wave, it’s likely a solid unit, assuming nothing inside has deteriorated over time.
I sometimes experience a faint "light buzz" when touching the back of my finger against the metal body of a mid-range ($1,000) Huawei laptop. I don’t recall similar sensations from a comparable mid-range Lenovo Yoga laptop, which also has a metal enclosure but a different PSU.
The Lenovo model came with a standard power brick featuring a 3-pin "clover leaf" connector at one end. The other ends connect to a plug with three metal pins (Line, Neutral, Earth) for grounding at an earthed wall outlet. Even though the 100W PSU is housed in a plastic casing, the inclusion of an earth pin suggests internal metal components are safely grounded.
The Huawei model uses a 65W brick with just two metal pins (Line and Neutral). Its two-pin design and two similar units (65W Ugreen, 100W Anker) have three-pin mains inputs, meaning internal metal parts aren’t grounded. These two-pin PSUs display the international "Double Isolated" symbol. Although this marking is present, I still notice occasional buzzing.
I suspect that pairing certain 2-pin power bricks with USB-C cables and ungrounded Y-class capacitors inside might cause low current and voltage spikes through the USB connection to the laptop’s metal casing. I don’t have all my PSUs and cables with me right now, so a thorough test isn’t possible.
In past projects as a design engineer, I examined power supply components for Safety Critical Parts—the essential elements that protect users from mains hazards. Having worked with 2MV high-voltage generators and 25kV DC transmitters, I wasn’t overly worried about returning my Huawei laptop due to safety concerns when a buzz was detected. I’ve also experienced several 240V mains shocks in my youth, when equipment quality was lower. While the Huawei PSU and USB leads appear safe, my third-party cables and Ugreen/Anker units seem to be the culprits for the buzz. Next time I’ll use a multimeter for a proper check.
From a safety perspective, it’s crucial never to run a metal-cased ATX PSU from a mains supply without an earth connection. If a fault occurs, the computer’s metal components will become live, along with any connected leads. Without a ground path, anyone handling the machine risks a fatal electric shock. In your configuration, you should ground the computer’s case to the building’s metal structure.
Simply connecting earth to equipment further down the line isn’t sufficient if the computer itself isn’t grounded. If needed, install a dedicated, robust earth lead from a screw on the back of the case to the building’s metalwork—use at least 1.25mm² wire, preferably 1.5 or 2.5 for safety. This wire must be able to handle fault currents strong enough to blow a fuse or trip a breaker.
Because I prefer visuals, this video should give you a clear picture of what I'm going through. Be careful with the mess, the noise, and those nosebleeds from my Celine Dion accent—plus the general chaos.
I liked the video a lot. I considered my workroom to be a bit disorganized, but you really improved it.
A few suggestions.
1). Installing all your components in an affordable second-hand case could reduce issues. It doesn’t need to be high-end, but keeping all internal cables (SATA, USB, Front Panel Audio, DC Power) secure would prevent them from being accidentally disturbed.
When using an ATX PSU in a regular case, the chassis connects via the case to copper pads on the motherboard’s underside, through metal standoffs.
Moreover, small metal protrusions on the motherboard backplate help ground ports (HDMI, DVI, VGA, Display Port, USB, Ethernet, etc.). This grounding is advantageous from an RFI/EMC perspective. Likewise, grounding the metal casting of hard disks to the case helps maintain consistent potential across all metal parts.
Not keeping everything grounded and disorganized can cause problems. Organize your setup and choose a suitable case. Visiting a repair shop for advice might be worthwhile.
2). Your earth connection with a Bulldog clip seems weak. I’d prefer a more secure termination using a nut and bolt. If I were, I’d drill a hole through the metal beam, but that’s probably not an option.
Your crocodile clip connections to the 12V 7A UPS battery are also somewhat loose. Using proper crimp tags or solder tags for the positive and negative spade terminals would provide a better connection.
The buzzing you feel when touching the terminals might stem from high-frequency ripple voltage in the charging circuits, or more likely, from an improperly earthed UPS. The same issue occurs when touching metal parts on the motherboard—those aren’t properly grounded.
It’s time for my evening meal. Cheers.
I can search for a straightforward open design case, but I’m really pleased my APU never exceeds 50°C. I set up the same configuration in Montreal, thinking it’s unnecessary to invest in an expensive case. Should I include a similar wire on the grounding prong of the UPS? I thought faulty power would always go to the same point and just follow there. Unless there’s a diode somewhere stopping the current, shouldn’t all the electricity just flow along the cables and end up in the earth?
Even though I appreciate keeping things calm, 50C is significantly below the highest temperature your A8-7680 can withstand. Checking the APU specifications revealed that the safe maximum case temperature is 74C. According to forum discussions, under stress conditions with Prime95, the APU chip can temporarily reach up to 90C.
Thermal safeguards in CPUs and APUs activate when the silicon reaches a critical threshold set by the manufacturer. The motherboard then lowers the voltage supplied to the chip to avoid overheating, allowing the system to continue operating. At 50C, your APU is simply running smoothly without any risk of damage.
For reference, older models like the AMD Phenom II X4 965 have a low upper limit of 60C, while newer Intel CPUs such as the 13900 reach up to 100C—well above water’s boiling point. With proper cooling, these high-end chips can operate at their limits for extended periods without harm, though electricity costs will rise. If they exceed safe levels, they automatically throttle to protect themselves.
If you upgrade your setup and use a metal case, you still have the option to leave the side panel off, especially if internal fans aren’t sufficient. However, keep in mind that your APU can handle temperatures as low as 70C comfortably, rather than 50C.
Unfortunately, a faulty power supply could lead to serious consequences. If the path to ground is compromised—especially if it includes your body—the risk of electric shock increases significantly. Current typically enters through the wall outlet and returns via the neutral terminal back to the power source. Diodes are unnecessary in AC systems because they disrupt the cycle, converting AC to DC.
"Bad electricity" will follow the least safe route down to ground, potentially reaching your body. Alternating current reverses direction hundreds of times per second, and inserting a diode can cause it to become DC instead. This forces the current to take lower-resistance paths—such as SATA cables, USB ports, or even your body—posing serious danger.
As previously noted, AC power enters through the wall outlet’s line terminal and exits via the neutral terminal back to the utility. Diodes are not used in these circuits. In fact, inserting a diode into an AC circuit blocks half of each cycle, converting AC to DC.
"Bad electricity" will seek the path of least resistance, possibly through cables, USB devices, or even your body. This is why proper grounding and safety measures are essential.