Removing C290 and testing it with a capacitor tester showed it to be open circuit.
We find that applying the test tone to these points gave sound out the left speaker but not the right speaker. Picture 4 shows the Amplifier and the Capacitors C289 and C290. Now we must test the other side of the 2.2uF capacitors C289 and C290. Next we check the inputs to the Amplifier at INL and INR ports with the test tone, again getting sound from both speakers, confirming the amplifier is working. The Speakers are fed from the Amplifier OUTL and OUTR ports, signals SPK_OUT_L and SPK_OUT_R.Īpplying the test tone at these points gave sound out of both speakers. Picture 3 shows the circuit diagram of the Audio Amplifier components. Picture 2 shows the Audio Chip (U14 a Realtek ALC861) and the Audio Amplifier Chip (U18 a Maxim Max9750) and the Volume Control. Luckily, on this laptop, all the main audio components are on the top side of the System Board, so it was not necessary to remove it from the base for diagnosis. The next step required the laptop top cover to be removed so the required audio components on the System Board could be accessed. Injecting a tone signal here showed that both speakers were working fine. Picture 1 shows the speaker connectors on the System Board, accessed by removing the keyboard. However, on checking by plugging in headphones, it was found that there was no sound in the right channel here either. If it was possible to repair it economically, it would be preferable to scrapping it and buying a new laptop, since it otherwise did everything required.Īs any computer technician will tell you, when a fault occurs in laptop speaker output, the culprit is usually the headphone jack socket failing to maintain the proper speaker/headphone contacts. This old laptop was working well until the sound from the right speaker disappeared.
0 kommentar(er)
