Wouxun Charger Repair

Some series of Wouxun chargers have the tendency to fail faster than you can blink your eyes. OK, I’m exaggerating a bit here, but the number of defective chargers is way higher than simple statistics could ever explain. Sometimes it’s just the 12V 1000mA switching power supply that gave up, but in most cases you will have to open up the charger.

A week ago I got one of these infamous chargers from a fellow HAM. A quick look at the circuitry explained a lot. Someone at Wouxun apparently tried to cut costs at the expense of reliability. One PNP transistor, the 2SB546 (or equivalent), can run a bit hot. On the PCB you can see that the designer made room for a heat sink, but somehow that 10 cent part never made it into the production process.

Cutting corners, a recipe for disaster

Three other components are missing too: a 56μH inductor (brutally bypassed by a piece of wire), and two capacitors. These parts are not essential for the reliability, nor for the charging process, but designed to kill most of the RFI the charger produces. Unfortunately I didn’t have these components in stock, but I will fix this later. First things first.

I picked up a few NEC 2SB546A transistors in a TO-220 package, added a small heat sink to one of them, and replaced the original one. A bit of thermal grease was applied too. Total costs: about $1. Don’t worry about the height, nor the 2mm the heat sink sticks out of the PCB – there’s plenty of room in the plastic case. The charger works great again, and now I have a nice spare on my desk.

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11 comments on “Wouxun Charger Repair

  1. I have gone through 3 Wouxun chargers in 2 months. Without a reliable method to charge the battery, the Wouxun radio has essentially been rendered useless! In my opinion, the Wouxun charger is PURE GARBAGE poorly designed and made with VERY poor quality parts!

    • The first generation was garbage indeed. The latest chargers (the ones accepting both mains and DC) are properly constructed. No issues have been reported by users. If you burn out three of the latest generation chargers in short succession, there must be something else wrong.

  2. I just cracked the cover on my newer (circa 2011) Wouxun charger with AC and DC input. I don’t see how to remove the circuit board from the top shell of the enclosure without possibly damaging the contacts to examine the parts side of the board, but I can tell you that the transistor on the left side has some form of heatsink on it. And yet it gets hot enough in normal operation to discolor the circuit board where the transistor is mounted. That’s frankly too hot!

    If even newer chargers are better, I don’t know. I sure would love an improvement over most of the Wouxun accessories if I could find them, actually.

      • I didnt see any screws on the bottom- hence my question… where are they? Do I have to pry off the rubber feet perhaps?
        thanks
        rich

      • In that case you don’t have the same charger as described in the article. The ones I have can be opened easily. Small rubber feet have to be removed first.

      • dont know. I didnt want to remove the rubber feet and not find the screws. Some plastic boxes simply use plastic catches along the edges… I guess I will pry off one of the feet and see.
        thanks
        rich
        ab0vo

  3. Mine stopped working properly. Took it apart and noticed a lot of residue on the pcb. It looks like the mfg used water wash flux and did not clean the boards. The flux is corrosive, absorbs water and causes conductive traces. Take the board out and brush it with a toothbrush under hot water. Dry it preferable with compressed air and it should work. Mine is ok now.

  4. I’ve got a newer (March 2013) dual slot charger I just picked up and when the battery is first inserted it makes a terrible squeal. I’ve got to assume that there are still components not included that ought to be there. I note this one doesn’t get insanely warm, but that squeal for the first 2/3 of the charge cycle is pretty annoying. If this one ever gives up the ghost, I tell you, I’m going to find a decent schematic to BUILD a better charger!

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