How do you remove the buzzer from this PCB whose solder side is inaccessible?

Question

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There is this buzzer in this UPS (uninterruptible power source) circuit. I want to remove it from this circuit because it make a lot of unnecessary noisy. Black-outs happen too much in my area. Sometimes they happen in the deep night, when I am sleeping, and this little buzzer wakes me up by freaking me up. I always immediately realize it when there is a black-out, so this buzzer is really not needed.

I am not able to de-solder it. Because the PCB is strongly embedded into the case by some very hard clippers. It just won't move.

How do I remove this buzzer from the circuit, or shut it up without removing? I don't plan to re-use it, so it is OK if it is destroyed in the process. I just don't want to get into risk of damaging any other part of the PCB.

Answer 1

You could quieten the buzzer by filling the hole in the top of the plastic. If you pour in something rubbery (hot glue could be good) then it would almost certainly muffle the sound.

To remove it, I'd crack the plastic with some pliers removing enough to heat the legs with a soldering iron.

Answer 2

I know the OP has probably solved this problem, but this is for anyone who might land here through google like I did.

I just disabled a piezoelectric buzzer exactly like this one.

Looking at the first picture included in the OP's post, the buzzer is the black cylinder with the hole at the top. See that seam running all around the cylinder? Take a very small flat head screwdriver, insert it into the seam, and wiggle the top off.

Beneath that is a shiny silver disk. Lift that out and throw it away. You'll see copper wire beneath that, but there's no need to touch that.

Lastly, snap the top of the cylinder back on. Now you'll barely be able to hear the buzz.

Answer 3

There may be an alternative choice. These devices are often resonant, and very loud at resonance. Putting a piece of cellophane tape over the opening may upset the resonance and cause it to be so quiet that you no longer need to remove it. And of course, the process is reversible.

Answer 4

I would use wire cutters to destroy it. Just a little bit at a time so as not to risk damaging the PCB.

Use large wire cutters like these.

Answer 5

First of all, the solder side is perfectly accessible. Well, it is not accessible now, but it will be if you remove the circuit board. From the pictures, it doesn't seem difficult. It looks like it is simply held in place by screws, plus a few board-mounted components that protrude through the enclosure.

Secondly, the buzzer may be wired in series with some other component: one of the neighboring jumpers or resistors. If you open that component, you silence the buzzer, without destroying it. A cut jumper or resistor can be replaced easily, if need be, since those are generic parts.

Like the hero in the movie, diffusing a time bomb, you have to cut the right one, without seeing the solder side traces. For that you can probe around their voltages with a multimeter from the component side, with the buzzer on and off. That's still a guess: better to do it with the circuit board out. Even with the board out and access to the solder, I'd still remove a resistor or jumper rather than the buzzer.

Answer 6

Option #1: I tried Jason's method on an APC brand UPS. Worked like a champ. Grab the black cylinder (marked 330-0004 or similar) and gently twist left/right until it comes loose. Problem solved.

Option #2: Using a flashlight to shine through the PCB from one side makes it easier it identify the correct contacts on the other side. Then use a soldering iron to remove the buzzer.

Option #3, for APC UPSs with a data port: Purchase a USB-to-RJ11 cable for about $15 and install APC PowerChute software. Disable the buzzer through software as originally intended by the manufacturer.

Answer 7

I have an inverter with the same problem so I stuck a toothpick in it. I had to get it stuck in just the right place to make it very very quiet but it worked for a while until i decided to unsolder the thing. Mine used to come on when the batteries were at a certain voltage even though they still had plenty of power and it was really really loud.

Answer 8

I tried covering the piezo hole, stuffing it with cotton and tape. But the gargle sound was still loud and more irritating.

De-soldering the buzzer was easy. A tweezer or nose-plier to pull and a soldering iron to just heat the soldered ends a little on the other side of the PCB.

The PCB screws were easy to remove. But probably the heavy heat-sink or the sticky gel keeping the LED in place made it seem as if something was still holding the PCB back.

Ah, peace at last. If it wouldn't have worked, i'd have taken that nose plier and crushed the blessed buzzer.

Answer 9

Just grip the buzzer's sides gently with needle nose pliers and twist clockwise and counter-clockwise about 20 times, like you're turning a knob. There are only two wires holding it to the board that will eventually weaken and break off cleanly.

For those searching, I did this to quiet a Verizon FIOS box that does not stop beeping after removing the back-up battery. Hopefully this will save millions of batteries being purchased just to stop the beeping.