Kingwin PC Computer Power Supply Tester, Digital LCD Screen, ATX/ITX/IDE/HDD/SATA/BYI (KPST-01)
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AI Verdict
The Kingwin KPST-01 is an aluminum-cased diagnostic tool that gives instant voltage readouts for PC builders, but its lack of load testing means it won't catch every failing PSU.
This tool is a massive time-saver for confirming a PSU isn't completely dead or wired incorrectly. Because it only tests idle voltage without applying a load, it cannot diagnose intermittent power delivery issues that cause gaming crashes.
If you need to diagnose random reboots under load, you need a digital multimeter and a software logging tool like HWiNFO64, or a dedicated load tester.
Regret Score™
Very High RiskLower is better — measures purchase-regret risk from real buyer complaints, review credibility, and product maturity
Issues discovered after purchase
Critically weak dimension
Amazon rating vs actual quality
Chance this product isn't for you
Pros
- 1.8-inch digital LCD shows exact voltage numbers for +12V, +5V, and +3.3V rails instead of just vague indicator lights.
- Aluminum casing survives drops and toolbox storage much better than standard plastic testers.
- Automatically bridges the 5V standby and ground pins to turn the PSU on without needing the paperclip trick.
- Supports a wide range of connectors including 20/24-pin ATX, 4/8-pin CPU, 6-pin PCIe, SATA, and Molex.
- Displays the Power Good (PG) delay in milliseconds to ensure the PSU is sending the right startup signal to the motherboard.
Cons
- Does not apply a load to the power supply, meaning a PSU that only fails under heavy gaming loads will still pass this test.
- Beeps continuously when testing modern power supplies because it looks for a -5V rail that was removed from the ATX spec years ago.
- Cannot test multiple peripheral cables at once; you must test SATA and Molex connectors one at a time to avoid false readings.
- Included instructions are practically non-existent, leaving beginners to guess what the PG values actually mean.
Dimension Scores
It accurately measures idle voltage to +/- 0.1V, but provides zero load testing, meaning it can't verify actual power output efficiency.
The built-in fault buzzer is obnoxiously loud and constantly triggers on healthy modern PSUs missing the obsolete -5V rail.
The brushed aluminum casing is a massive step up from the flimsy plastic shells found on cheaper generic testers.
The port layout is straightforward, but the ATX connections are tightly spaced, making it difficult to unplug stiff 24-pin cables.
Best For
- PC flippers testing bins of used or older ATX power supplies before building.
- IT helpdesk techs who need to quickly rule out a completely dead PSU before swapping motherboards.
- Custom PC builders who want to verify pinouts on custom-sleeved cables before plugging them into components.
Not Recommended For
- Gamers trying to diagnose random system crashes or reboots that only happen during heavy GPU loads.
- Overclockers who need to measure exact voltage droop (vDroop) under stress.
Watch Out For
- The -5V beep of death: Modern PSUs don't have a -5V rail, so the tester will flash 'LL' and beep loudly on a perfectly healthy new unit. You just have to ignore it.
- No load testing: This only checks if voltage is present at idle. A PSU with blown capacitors might show perfect 12V here but instantly crash your PC when you launch a game.
- No hot-plugging: You must plug the 24-pin and CPU cables into the tester before flipping the PSU power switch, or you risk damaging the tester.
- Peripheral overload: If you plug in a SATA cable and a Molex cable at the same time, the tester can short out or give false readings. Test them one by one.
Full Specifications
| UPC | 812348013662 |
| ASIN | B07VXSFXP1 |
| Brand | Kingwin |
| Color | black |
| Style | DIGITAL LCD |
| Item Weight | 0.317 ounces |
| Manufacturer | Kingwin |
| Power Source | Dc Power Supply |
| Measurement Type | Voltmeter |
| Item model number | KPST-01 |
| Specification Met | CE, UL |
| Product Dimensions | 3 x 2 x 1 inches |
| Item Dimensions LxWxH | 3 x 2 x 1 inches |
| Item dimensions L x W x H | 3 x 2 x 1 inches |
| Global Trade Identification Number | 00812348013662 |
What Buyers Say
The most recurring theme in user reviews is the sheer panic caused by the continuous beeping on brand-new power supplies. Because the tester checks for an obsolete -5V rail, buyers frequently assume their new Corsair or EVGA unit is dead out of the box until they read forum posts explaining the quirk. Beyond the noise, users love the aluminum build and the exact LCD readouts compared to older LED-only testers. Many experienced builders note that it only catches completely dead units, not dying ones that fail under load. The lack of a proper manual is a universal pain point.
“Scared the crap out of me when it started screaming at my brand new 850W PSU, but once I learned modern units don't have a -5V rail, it became a handy little tool.”
Common Praise
- The 1.8-inch LCD screen is bright and easy to read from a distance.
- Aluminum housing feels premium and survives being tossed into toolboxes.
- Instantly turns on the PSU without needing to mess with paperclips.
- The PG (Power Good) ms readout helps diagnose weird motherboard boot loops.
Common Complaints
- Piercingly loud beep when testing modern PSUs that lack a -5V rail.
- Zero instructions included in the box to explain what the PG values mean.
- Ports are very tight, requiring serious force to remove the 24-pin cable.
- Doesn't catch power supplies that only crash when the GPU ramps up.
Ownership Tips
- The LCD screen scratches easily if left loose in a bag with screwdrivers.
- You have to memorize the acceptable PG range (100-500ms) because it's not printed on the device.
- If you accidentally hot-plug a PCIe cable while it's running, the screen will sometimes freeze until you restart the PSU.
Frequently Asked Questions
Why is my tester beeping continuously and flashing 'LL' on the -5V reading?
The -5V rail was removed from the ATX specification years ago. The tester is looking for it, can't find it, and triggers an alarm. If you have a modern PSU, your unit is fine and you can ignore this beep.
Can this tell me if my power supply is causing my games to crash?
No. This tester does not put a load on the power supply. It only verifies that the PSU can output the correct idle voltages, which won't catch a unit that fails under heavy GPU draw.
Do I need to use the paperclip trick to turn the PSU on with this?
No. Plugging the 24-pin ATX cable into the tester automatically bridges the power-on pin and ground, forcing the PSU to start up.
Can I plug in all my cables at once to test them?
No. You should plug in the 24-pin ATX cable and only one peripheral cable (like a single SATA or Molex) at a time. Plugging in multiple peripherals simultaneously can damage the tester.
What does the PG number on the screen mean?
PG stands for Power Good. It shows the delay in milliseconds (ms) it takes for the PSU to stabilize and tell the motherboard it's safe to boot. A healthy PSU usually reads between 100ms and 500ms.
Does this work with custom sleeved cables?
Yes. It is highly recommended to use this tester on custom cables to ensure the pinouts are correct before plugging them into your expensive PC components.
Buying Guide
When buying a basic power supply tester, you need to understand its limits. This tool is a 'go/no-go' gauge for idle voltage — it tells you if the cables are wired correctly and if the PSU turns on. It does not simulate a gaming PC drawing 600 watts. If your PC is completely dead, this will tell you if the PSU is the culprit. If your PC only crashes while playing heavy games, this tester will likely tell you the PSU is fine even if it's actually failing.
PG (Power Good) Delay
Think of this as the PSU clearing its throat before speaking to the motherboard. It's the time (in milliseconds) it takes for the power to stabilize. If it's too fast or too slow, your PC won't boot.
Voltage Rails (+12V, +5V, +3.3V)
These are the different 'flavors' of power your PC needs. 12V runs the heavy lifters like the graphics card and CPU, while 5V and 3.3V handle smaller things like USB ports and storage drives.
-5V Rail
This is an ancient power requirement used for old floppy drives and ISA slots. Modern power supplies don't have it, which is why this tester will beep at you.
Alternatives
If you need to diagnose random crashes under heavy gaming loads, skip this and look for a digital multimeter to measure 12V droop manually, or invest in a dedicated PSU load tester.
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