What voltage is the power adapter for the Mercury router? The new and old models have the same plug but different voltages; picking the wrong one can really burn out the machine

cousin moved last month, and the router's power adapter was lost in a bag, leaving the machine safely in the weak current box. He rummaged through his boxes and cabinets to find an old power supply with the Mercury logo, left behind by the old Mercury from his college dorm after retirement. The plug fit perfectly, and when plugged in, the light really brightened. I passed by his house and saw that scene, so I told him to quickly unplug it—the two power supply stickers were 3V different. This is worth writing about because the Mercury router's power supply is more common than expected: the plug is one for the entire system, but the voltage is split into two sets of for the old and new models.

to get to the point: the Mercury you commonly see at home is probably 12V 1A

I checked the bottom shell stickers of all the Mercury units at home and at my relatives' and friends' homes. For nearly ten years of dual-frequency gigabit models, almost all power supplies are 12V 1A. My cousin's D191G is 12V 1A, and my childhood friend's M6G with Mesh networking is both 12V 1A, and my colleague's MAC1200R is also 12V 1A. The D196G and D19G, these siblings, are also listed as 12V 1A in teardown materials.

9V that tier is an older generation. The Mercury MW310R and MW150R 100Mbps single-frequency machines became popular around 2013 and were frequent visitors to student dorms and old buildings. The original power supply was 9V 0.6A. Many of these machines are still in service, more than enough to serve as an AP for an IoT private network or for elderly users. model and hardware versions are clearly on the bottom shell stickers, so you can see them at a glance.

By the way, when sent back to my home M6G sub-router JD and SF Express sent a bare phone without a power supply, customer service specifically reminded me to use a 12V 1A connector, which confirmed this spec. As for higher-end AX models and devices with USB, the current requirements may be higher. Don't copy 1A—just follow the sticker.

cousin's mess scene: plug tightly fitted, sticker poor 3V

came back to tell me about the night my cousin. The original D191G head was lost after moving, and the old power supply he found in a drawer was left behind after his university MW310R was retired. Both heads are Mercury logos, and the DC round ports are exactly the same size, so they fit in without being too loose or tight. When the lights came on, he was quite proud, saying he saved more than ten yuan.

I asked him to flip out the bottom shell stickers of both machines and look at them: the D191G sticker says Input: 12V == 1A, and the MW310R says 9V == 0.6A. In other words, he plugged a 9V plug into a machine that needed 12V. This combination is undervoltage; the machine won't break down immediately, but the WiFi will become half-dead—he noticed the living room WiFi was intermittent that night, and the 5G band disappeared altogether. He thought the antenna had been damaged by moving.

the real danger is the opposite. If he had pulled out a 12V plug and plugged it into a 9V old Mercury, the capacitor and voltage regulator circuit in that 9V machine would already have tight voltage tolerance. Long-term overvoltage would cause the capacitor to bulge and halve in life, or burn out on the spot. Tenda's official website specifically states in the AC10 description: "When using DC power supply, use a 12V-1A adapter, do not exceed 12V." The manufacturer included this in the documentation, showing that someone really had this issue. I use a Mercury Tengda at home, so don't mix these two connectors. although I've rated both brands as pretty much , they all use a 5.5mm wide socket, which makes it easier to get the wrong connector.

inserted in the wrong direction, the consequences are completely asymmetrical

to explain this thoroughly, remember one thing: just because plugs are the same doesn't mean they can be interchangeable. If the voltage is wrong, the direction will be different, and the outcome will be different .

A typical example of a

undervoltage machine is that the power light can be lit but is dimmer than usual, or it simply flickers faintly, and WiFi can be found but cannot connect. My cousin's D191G that night was exactly like this. Overvoltage doesn't have much prelude; old machines have limited internal design margins, with 12V plugged into a 9V circuit, and the voltage regulator chip and capacitor are the first two parts that can't hold up.

there's another detail that's easy to overlook: the polarity of the DC head. The entire Mercury system is positive on the inside and negative on the outside, marked with a dot plus a plus sign inside the circle. Third-party power supplies with inverted polarity (rare but some) still have issues. Before buying, check the polarity diagram on the adapter label — it's more reliable than anything else.

before buying a new one, you have to pass three hurdles

confirming you're buying a new power supply, don't just search for "router power supply" and place an order. On e-commerce sites, 5V, 9V, and 12V are mixed, and the best-selling one may not be what you want. When I put on a new hairstyle for my cousin, I followed three screening steps:

first level, voltage is exactly right. the machine sticker says 12V, buy 12V; if it says 9V, buy 9V—there's no 'about the same' is fine. My cousin's D191G was bought at 12V. When that old man with 9V stored it in the spare parts box, I asked him to stick a note clearly stating, '9V is for Old Mercury only,' so he won't get it wrong next time.

second level, the current should be only high, not too low. 12V 1A machines can use 12V 1.5A or even 12V 2A connectors, so the machine can draw power on demand without forcing a run; On the other hand, a 12V 0.6A head with a 1A machine struggles, as it heats up under full load for long periods, and over the years, it ages on its own. Copying the original 12V 1A specifications is the most worry-free.

Level 3: DC head size. Mercury and Tenda use a 5.5mm outer diameter large mouth, with a common inner diameter of 2.1mm, and a few 2.5mm variants that have a 0.4mm inner diameter difference and can loosen when inserted. Use a ruler to measure the pin hole of the original head, or directly ask customer service, "5.5× 2.1 is correct." Here, you need to distinguish it from Xiaomi's routers. Xiaomi uses a 4.0×1.7mm small , which is one size smaller than the Mercury, so the two connectors physically can't fit into each other's heads, which is actually a good thing.

price, third-party qualified products cost just over ten yuan, while original ones cost only twenty or thirty yuan. I bought a 3C certified, third-party 12V 1A for my cousin, 15 yuan with free shipping, and used it for over a month without any issues. I advise you not to touch the 9.93 yuan free shipping option. Overrated current is a major issue; the 1A rating doesn't actually fill the battery, and the machine loses power and restarts once fully loaded.

the power supply still doesn't work? First, don't rely on new hairstyles

one situation is easy to blame on a new power supply: the original connector used by the machine has aged for five or six years, and the output voltage is 'normal when no-load but still under load'. I tested this method once on an optical modem: set the multimeter to DC voltage mode, and the no-load output is 12V, which is normal. When the machine is connected and output is under load and the output drops to just over 9V, that end is useless. cousin's optical modem was diagnosed this way, the same method as router connectors. If you don't have a multimeter at home, the simple method is to find a different head of the same specification and cross-cross it—you'll know at a glance.

if you replace the power supply to ensure the problem is fine but the machine still doesn't work, then it's not the power supply's fault. Follow this order below:

look at the lanterns first. Mercury's SYS lights follow the opposite rules: the new model stays on normally, while the old model flashes slowly. Don't panic when you see the light state is different from what you remember. The power light is completely off. First, check that the socket and power strip are powered before suspecting the machine.

If the

light is normal but restarts repeatedly, there are two possible reasons: one is firmware issues, manually download the Mercury firmware from the official website and upgrade to the hardware version; Second, you need to restore the factory setup, but that requires reconfiguring a broadband account and WiFi. Before starting, copy what needs to be copied first, always put the reset last.

situation? Take it personally

Here's a wrap-up

order: flip through the bottom case to take a photo of the sticker and save it on your phone, follow the sticker specifications and pass the three checkpoints to place an order. Once in hand, check the light on the power strip without loading, then connect the device and observe for half an hour. My cousin's D191G was replaced with a new 12V 1A headset, so the living room WiFi was stable that night, and the 5G band was back, costing less than twenty yuan for the whole trip. The power supply is the cheapest yet most easily overlooked accessory on a router. Recognizing stickers but not logos can save the entire machine.