[Solved] Laptop speaker not working - Page 1
Forum section: electronics / beginners

author: DisasterNow
author_rank: Regular Contributor
timestamp: August 09, 2025, 01:57:33 pm
content: Hi, I have a Lenovo v110 laptop (it's 8 years old), and I can't hear any audio from the internal speaker (there's only one). If I plug my headphones into the appropriate jack, I can hear audio (so in theory the Realtek ALC3240 chip is working).I disassembled the laptop to inspect the speaker, but when I removed the connector, it broke and deformed (it's no longer usable).Is there an easy way to check if this speaker is still working? (I read about connecting a 9V battery to the two cables?)But I also suspect that the problem might be due to the Realtek chip detecting the headphones even when they're unplugged, which inhibits the internal speaker's audio; does the HP_DET signal perform this check? How could I check if this is the problem?I've attached some photos, including a diagram of the affected parts.Thank you.

author: Grandchuck
author_rank: Super Contributor
timestamp: August 09, 2025, 03:04:44 pm
content: You can do a speaker "click test" with an AA or AAA battery

author: DisasterNow
author_rank: Regular Contributor
timestamp: August 09, 2025, 03:42:54 pm
content: Quote from: Grandchuck on August 09, 2025, 03:04:44 pmI tried connecting the terminals of an AAA battery to the speaker, and absolutely nothing happens. I don't have another speaker to test whether the audio signal reaches the motherboard speaker connector (the speaker was connected to the two L+ and L- pins from the ALC 3240) when the headphones are disconnected.I might try turning on the laptop, if possible, with the lid off, to see if a signal reaches the L+ pin of the connector (with the speaker disconnected) while listening to audio.

author: Zero999
author_rank: Super Contributor
timestamp: August 09, 2025, 04:21:50 pm
content: Quote from: DisasterNow on August 09, 2025, 03:42:54 pmAssuming the battery you used to test it is good, then the speaker must be bad.If you don't have another speaker, you could try playing a sine wave on the laptop and measuring the voltage on the speaker connector on the motherboard with a multimeter set to voltage mode.

author: Gyro
author_rank: Super Contributor
timestamp: August 09, 2025, 04:43:02 pm
content: Do you have a meter to perform a basic continuity test of the speaker?Replacement V110 speakers are readily available on ebay.

author: DisasterNow
author_rank: Regular Contributor
timestamp: August 09, 2025, 04:47:22 pm
content: Quote from: Zero999 on August 09, 2025, 04:21:50 pmYes, the 1.5V AAA battery is working, so I think the speaker is faulty. Before ordering a new one, I'll run the test you suggested; I can do it with an oscilloscope. However, I need to find a connector in stock that plugs into the motherboard's speaker socket, with the two free wires, and I'll try to see the signal on the L+ terminal (referred to the laptop's ground). I'll update after the test, thanks.

author: DisasterNow
author_rank: Regular Contributor
timestamp: August 09, 2025, 04:50:53 pm
content: Quote from: Gyro on August 09, 2025, 04:43:02 pmYes, I have a tester. So far, I've only verified that continuity is flowing from the ALC3240 pins to the speaker connector pins on the motherboard. So, even passively, could I use the tester to determine if the speaker is dead? Thanks.(exactly, the spare part is easily found for this Lenovo v110- 15isk laptop).

author: themadhippy
author_rank: Super Contributor
timestamp: August 09, 2025, 05:29:45 pm
content: if youve got a scope attach it to the speaker and shout at/tap the speaker

author: Gyro
author_rank: Super Contributor
timestamp: August 09, 2025, 05:42:29 pm
content: Quote from: DisasterNow on August 09, 2025, 04:50:53 pmYes, you can check continuity of the speaker, it should read around 3 Ohms DC resistance (assuming it is a 4 Ohm audio impedance speaker [, Edit, maybe it is marked]). If it is open circuit, there is no longer any doubt.

author: DisasterNow
author_rank: Regular Contributor
timestamp: August 09, 2025, 07:01:55 pm
content: Quote from: themadhippy on August 09, 2025, 05:29:45 pmOut of curiosity, I'll try it with a working speakerQuote from: Gyro on August 09, 2025, 05:42:29 pmI found another speaker I had in stock. I tested it with a battery (and it clicks) and it reads 9 ohms (it should be 8 ohms, but that means it's working). The speaker on this Lenovo, however, with the resistor, is open circuit (and it doesn't respond to the battery). It's not written on the speaker, but as you can see from the diagram, it should be 4 ohms.Before ordering the replacement, I just want to verify that the signal is coming from pins 35 and 36 (L+ and L-) of the 3240 chip. I don't want the signal output to be damaged as well. But in that case, I could always use the R+ and R- signal outputs, which go to the speaker connector, but which weren't used (it would have been needed for a second speaker, which they decided not to include on this low-cost device). Thanks.

author: amyk
author_rank: Super Contributor
timestamp: August 10, 2025, 02:16:05 am
content: Temporarily connect the working speaker to the output terminals and play some audio to test it.

author: DisasterNow
author_rank: Regular Contributor
timestamp: August 10, 2025, 06:43:32 am
content: Quote from: amyk on August 10, 2025, 02:16:05 amI have two spare speakers (they were from an old laptop I disassembled), but their impedance is 8 ohms (compared to the likely 4 ohms of the faulty one in this Lenovo). I don't want to damage the ALC3240 amplifier, even though in theory nothing should happen; I'd probably just have half the power, if I'm not mistaken.I've already cut the wires from the faulty speaker, connected its bent plug to the motherboard socket, and later, if I can turn the device upside down, I'll try an MP3 file of a sine wave, seeing if I get the output waveform at the connector. Thanks.

author: amyk
author_rank: Super Contributor
timestamp: August 10, 2025, 08:01:06 am
content: No chance of damage with using higher impedance speakers; they'll just be quieter at the same volume setting. You can even connect earphones/headphones for a test, but chances are you'll want to turn down the volume all the way first as they can be very sensitive - in a typical PC audio chain, damage by excessive power is most likely going to happen to your ears before the speakers, and the speakers before the amp.

author: DisasterNow
author_rank: Regular Contributor
timestamp: August 10, 2025, 12:22:47 pm
content: Quote from: amyk on August 10, 2025, 08:01:06 amI'll try this test using the 8-ohm speaker from a Sony notebook. Maybe today I'll be able to test the audio output. Thanks for the suggestionEdit: I tried connecting the speaker I had in stock to my laptop, and the sound plays well. Problem solved, I'm buying a replacement. Thanks for the advice

author: Grandchuck
author_rank: Super Contributor
timestamp: August 10, 2025, 06:43:33 pm
content: Good work

author: DisasterNow
author_rank: Regular Contributor
timestamp: August 11, 2025, 04:25:48 am
content: The problem is solved, but out of curiosity, I tried displaying the audio output signal on the oscilloscope, also trying an MP3 file of a sine wave. I expected to have a signal close to zero when the audio was off, and to see a sine wave while I was listening to it; instead, the signal is always noisy, and honestly, if I hadn't had the speaker to check if the audio output was working, I wouldn't have been able to tell if the out channel was working by viewing the oscilloscope; the wave always seems the same (and nothing resembling a sine wave). I've never displayed the audio output of a laptop with the oscilloscope, so I don't know if this is normal or if I made a mistake in the measurement. In any case, I can hear the audio in the test speaker quite well.

author: Zero999
author_rank: Super Contributor
timestamp: August 11, 2025, 08:25:52 am
content: Quote from: DisasterNow on August 11, 2025, 04:25:48 amThere could be several reasons for that.How was the oscilloscope connected? Was the laptop run off a battery or mains? Is it connected to anything else? If the laptop shares a ground with the mains and the amplifier has a bridged output, then you would have short circuited one side through the oscilloscope ground, causing the amplifier to shut down.

author: DisasterNow
author_rank: Regular Contributor
timestamp: August 11, 2025, 01:10:41 pm
content: Quote from: Zero999 on August 11, 2025, 08:25:52 amHi. The battery was disconnected; I was only powering the laptop from the 230V mains. The laptop's plug has a ground connection. I connected the oscilloscope's ground to the laptop's ground, while I took the signal from L+ just before the speaker (I also tried the L- cable). I think I did the right thing; the probe's reference ground was zero potential, the motherboard's ground (which will also be referenced to the mains ground). The signal was noisy, unreadable... Connected like that, why would I risk a short circuit? Maybe by powering it only from the battery, would I have gotten a better signal? Thanks.

author: amyk
author_rank: Super Contributor
timestamp: August 12, 2025, 02:43:58 am
content: This is known as a "capless" amplifier; you cannot measure the output relative to ground, because it's not referenced to ground.Some background information:https://www.ti.com/lit/gpn/tpa4411https://www.analog.com/en/resources/app-notes/an-1056.html

author: DisasterNow
author_rank: Regular Contributor
timestamp: August 12, 2025, 07:25:23 am
content: Quote from: amyk on August 12, 2025, 02:43:58 amThanks for the documentation. So if I understand correctly, downstream of the ALC3240 chip (for which there's no documentation; I only have the schematic of how it's connected on this motherboard), the output signals are not filtered by any capacitor to block the DC current, and in this situation the reference for the two output channels is not GND but something else.In such a situation, listening to the audio of a sinusoidal signal, would there be a way to measure it with oscilloscope probes that would allow me to see a 'clean' signal, for example, on the L output of this amplifier? (Without causing any damage). I also have the differential probe, in case it would be useful. Thanks.

author: Zero999
author_rank: Super Contributor
timestamp: August 12, 2025, 07:46:23 am
content: It could be a class D output, which uses PWM and in this case the speaker's inductance filters out the high frequency switching.Have you tried using two oscilloscope inputs in differential mode? At the very least, you should see some high frequency PWM, which could be hundreds of kHz.

author: DisasterNow
author_rank: Regular Contributor
timestamp: August 12, 2025, 12:38:33 pm
content: Quote from: Zero999 on August 12, 2025, 07:46:23 amI tried a differential probe, but the signal was still confused, with interference; in fact, it sounded like two signals intersecting. Beyond that, the strange thing is that I would have expected, for example, that by plugging in the headphone jack, the signal on the speaker would be absent, but in practice it remains the same (note: if I actually plug in headphones, the speaker doesn't emit any sound). Anyway, the important thing is that the problem has been resolved; measuring the output waveform was just my curiosity. Thanks.

author: BILLPOD
author_rank: Frequent Contributor
timestamp: August 12, 2025, 01:02:45 pm
content: Good Morning DisasterNow, Here is a tone generator to have fun with.https://www.szynalski.com/tone-generator/

author: DisasterNow
author_rank: Regular Contributor
timestamp: August 12, 2025, 02:00:48 pm
content: Quote from: BILLPOD on August 12, 2025, 01:02:45 pmThanks, I knew that site. This time, however, I preferred to download an MP3 file with a sine wave signal. The problem isn't the signal, but the measurement at the speaker output, where I get an unspeakable signal. But as others said above, I think it depends on where I place the probe's ground reference...Edit: looking at the audio chip schematic, to have a 'decent' speaker output waveform on the oscilloscope, perhaps you should use the alc_gnd pin as a reference for the (differential) probe.