A118C static noise audio recording problem

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budster

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Hi, I recently bought a A118C dashcam. During the first couple days, the recorded audio/video is fine. Afterwards though, the recordings all have a loud static noise in the audio that does not sound right. Are there known issues for this dashcam with the static noise in the recorded audio? I have uploaded a sample video to youtube at

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Can anyone review and let me know what you think? Is there any simple fix for the problem or only option is to return it for an exchange? Thanks for any advice.
 
Try a different power supply/phone charger/USB powerbank to see if it is the power supply or the camera at fault.
 
Nigel said:
Try a different power supply/phone charger/USB powerbank to see if it is the power supply or the camera at fault.
Click to expand...

Thanks, I will try that suggestion later. Won't have access to the dashcam until end of the week as it's installed in a relative's car.

I found there's another thread about a static noise issue at https://dashcamtalk.com/forum/threads/a118c-fix-for-microphone-static.10799/ where someone found the microphone was misplaced. Had a few related questions. First, are there instructions on how to open up the A118C and would doing so void the warranty? Second, where is the correct placement of the microphone? The person in that thread fixed the issue by taping the microphone on top of the capacitor, but I'm not clear if that's where it's supposed to be. Since the audio during the first few days of recording was fine, I don't think the microphone in my problem dashcam can be under the capacitor's black tape like the other person found, but I guess the dashcam would have to be opened up to check for sure.
 
Last edited by a moderator:
no real instructions to open it. just 4 easy to see phillips screws on the mounting plate side (2 are in the curved part either side of the lens). you'll need a small thin screwdriver to get them. if you're careful about removing the sticker covering one of the screw holes, it shouldn't void the warranty. i usually use an exacto blade to remove them, and do it slowly.

to me this (literally) sounds like an intermittent connection on the mic - maybe a cold solder joint - because it seems tied to physical motion of the car and/or engine vibration. unfortunately not simple to fix yourself since it's such a fine wire (something like 30 awg if not smaller). you can try anchoring the microphone better so it doesn't move with the vibration of the car, but that may not cure it completely.
 
This problem kept bothering me so I decided to make an early trip to get access to the dashcam. I took some more recordings and am reviewing them and will provide more details later. In summary though, it seems the static noise problem is intermittent.

Here's some photos first of the dashcam opened up. Does anyone spot something that could cause the problem? The microphone was on top of the capacitor and held there by some kind of black cloth tape over the microphone's wires.


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So I made multiple test drives on local roads. First, made one drive before opening up the dashcam to confirm problem still exists. In this recording, there was a lot of static noise for the 1st 10 seconds and then it cuts out immediately to a softer static noise background, but the recorded sound is very muffled and not normal. Here's a youtube video clip of this.


Afterwards, I opened up the dashcam and put some folded electrical tape under the microphone in hopes that it would stick to the top of the capacitor better. Here's a picture of the end result.

IMG_0198.JPG

I had thought about moving the capacitor to the side of the case where the labeled mic opening is, but didn't want to risk breaking the microphone wires as it looked like it would need to be bended awkwardly to do so.

Then made a couple test drives and everything sounded fine so I was thinking the issue was fixed. Decided to make one more test drive and after about 1 minute of driving, the loud static noise came back and lasted for the remainder of the 5 minute drive.

Then made another test drive with the dashcam powered by a USB powerbank and there was no sound issue.

Switched back to using the car charger and for the first 4 minutes everything sounds fine. Then in about the last 15 seconds, the loud static noise comes back as the drive is about to end and I'm about to park. Here's a youtube clip where the static noise starts coming back around the 01:25 mark.


I ran out of time to do anymore testing.

Could any conclusions be made after all this? I want to test more with the dashcam powered by the USB powerbank as I only got one chance to try with it. Could the static noise really be caused by a bad cigarette power adapter cable?
 
I guess a faulty capacitor in the power adapter. I've heard very similar noises from high voltage capacitors, unusual for a low voltage one though.
 
Did some more testing and can now reproduce the problem using a USB powerbank as well as a different car charger. Even moved the dashcam to a different car and experienced the problem with the different power sources. Maybe like someone else mentioned, problem is with the microphone's connection inside the dashcam. Going to try to get it exchanged with the ebay seller.
 
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