[Android Head-Units] np27np27:
S100 S150 SD/USB/System sound problem fix. [emoji7]

For those of us unlucky users who's sound is not working from various areas of the unit, I think I have finally found the fix.

The symptoms of the problem are no sound from media player, navigation, TV, android sounds and installed android software. Radio and DVD seem to work fine. [emoji37]

So I fixed this by reflowing several areas of the main board that lives behind the screen. My unit is a C012 so your board may look a bit different, but I would guess most are the same.

First remove your unit from the car and take off the screen panel from the front of the unit. On my unit there are two screws below the screen that come out first and then the front fascia and screen come off. Then unclip the flat cable to release the screen from the unit.

Then on the board behind the screen you will see a large metal plate that covers the processor and various other chips. Remove this cover by desoldering at each corner, and the cover should pop off.

Your board should hopefully look something like this:

Now unclip the various flat cables and connectors from the board and remove the four screws from each corner and remove the circuit board from the screen. Remove any stickers that are on the chips.

Now for the reflowing! You need to cover and protect the vulnerable areas of the board using aluminium foil from you heat gun. We are going to heat up the main Samsung processor, some nearby chips and the codec chip, which is where I suspect the problems come from. Cover all other areas of the board carefully to minimise the chances of frying other components [emoji16]

Your board should now look something like this:

Don't forget the small chip below the main processor in the picture, the codec chip.

Now for the reflowing, this procedure worked for me, hope it's good for you too. I have a heat gun with two settings, low and high! Low is about 350 degrees Celsius and high is around 600.

Place the board on something heat resistant like a piece of metal. Now flip the board over and heat all of the back of the board on low temperature for 1 minute. Use wide circling motions and don't hold the gun too close.

Then turn the board over to the chip side, and heat the exposed areas on high setting for no more than two minutes. Again use circle movements and do not heat any area directly for more than a moment! You want to heat all areas quickly and evenly and try not to move the board.

After this DO NOT move the board or press on any components, turn off your gun and leave the board to cool for at least 30 minutes for the solder to set well.

When cool, reassemble all the the cables, the processor cover (may need to resolder) the screws, and attach back to your unit.

Turn the unit back on, and with any luck you will have your sound back again [emoji1] [emoji2] [emoji3] [emoji4] [emoji5]

If it's still not working then maybe try the reflowing again and concentrate the heat on the processor and the codec chip.

My reflowing worked first time, I hope it does for too. And let's all hope it lasts and does not require doing again and again [emoji30]

For those not confident on the reflowing process, have a look at the numerous YouTube videos on it for more tips and instructions, especially Xbox reflowing.

Good luck [emoji6]