Mazda 6 Bose amp fault

**rainy1505** · 22nd June, 2019, 11:14 AM

Thanks for info

I will order them ASAP

**rainy1505** · 14th August, 2019, 04:33 PM

I have changed all three SMD's
mazda bose amplifier.jpg
and everything is working great now, no more machine gun sound!
I'm happy now

Thanks guys!

**Thiaga** · 14th August, 2019, 06:49 PM

Hi,
I have the exact same problem, machine gun popping sound
I have followed your steps and I am getting 2 voltage readings from the ST2L05 to the capacitor, the reading changes from 2.5V to 1.25V.
So I am assuming this is not a stable voltage and will proceed to replace the 3 chips.

I was wondering how you guys have been replacing these chips, with a hot air rework station?
Any tips with the replacement will be appreciated!

Also, is there any information on why this "machine gun sound" happens and why these chips are failing? Ans is there any way to prevent this in the future?

Thank you

**Thiaga** · 14th August, 2019, 06:54 PM

Hey,

I am having the same problem and hoping to replace the 3 chips as well.

What tools and equipment did you use for the replacement?

Thank you!

**abunfe** · 27th October, 2019, 11:19 PM

Originally Posted by attilaa0

First change the stabilizer and do not solder the DSP,check the voltages 1,25V and 3,3V also and check also with oscilloscope ,the line must be stable without any noise when visulizing with scope,if it's ok only after that solder the new DSP.And if still not work then change the CS42438.

So I have a question, on the oscilloscope test, do I check between the points 1,25V and 3,3V? Or do I ground my lead and check. Also I noticed that if i move the board it will start doing to machine gun sound. At first I thought it was the wires, but just the motion of moving the board would cause the noise. Would you know why that is? And thanks before hand.

**MrRepair** · 28th October, 2019, 08:25 AM

Look at the head unit, you see it will take a BTL output IC. Fit it and the other missing components. Then re-wire the vehicle without the amplifier. You loose the subwoofer. I find this a faster & cheaper option.

**Shanna1978** · 18th May, 2020, 09:12 AM

Hi I see this an old thread but I just have no sound on my bose, what 3 chips get replaced as I couldn't open photo to view, also do any need to be programmed. Thanks

**rainy1505** · 6th July, 2020, 10:56 AM

chips
ST2L05-3300
CS42438
DSPB56374AE or SCB56374AEB is the same

**harjoe** · 21st July, 2020, 09:26 PM

Hello guys, I have the same problem with amp.
can someone give me the repair solution?

Thanks

**nohits** · 16th August, 2020, 05:56 PM

Hi . I took amplifier out of car becouse I wanted to put new cooling paste on chips and resolder problemable parts to prevent silent or machinegun sound. While I put the amplifier back to car, no sound comes from speakers. I measured all important power points on PCB (including stabilizers) and everything is ok - 12V, 12V Enable, 3.3V and 1.25V. Remote pin (AMP CON) from radio to activate amplifier have only 10,5V, but I suppose it is not a problem becouse 12V Enable pin on 5V stabiliser gives 11.45V after turning "starting key" to ON position.
No shorts on soldered parts. Cooling paste is unleaded. I suspect CS42438 chip, but there is no power output to check. Only autdio outputs. I don't have osciliscope, only TRMS multimeter.

Do you have any ideas guys? There is picture of my PCB. That mess on board is rest of varnish after cleaning for better parts visibility.

**nohits** · 2nd September, 2020, 07:04 AM

Update: i did bypass from input pins directly to end level chips, still silent. Its warm but muted. Solving this problem could be activating this chips. Does somebody have datasheet of Bose chips?

**nikolat** · 11th September, 2020, 09:59 AM

Any new info? I also have BOSE amp and after replacing all chips I still dont have sound?! Checked power on board and I am getting normal voltage but speakers are silent?!

**nohits** · 12th September, 2020, 06:05 AM

Hi, I hadn't much time, but this week I will try to solve it

**nohits** · 13th September, 2020, 09:45 AM

** UPDATE in next reply ! **

**nohits** · 13th September, 2020, 02:23 PM

So I did little researsch. And have new informations about Bose chips:

Bose 272154 - TDA8566 (NXP) - 2 x 40W / 2ohm amplifier - 2x19W/4ohm/0.5% THD - 2x25W/4ohm/10% THD - analog control (On/Mute/Standby) by pin 20 (MODE)
Bose 291618 - TDA8595 (NXP) - 4 x 45W / 2ohm amplifier - 4x20W/4ohm/0.5% THD - 2x30W/4ohm/10% THD - I2C (without Mute option) or analog control by pin 29 STB (analog by pin 28 - ADSEL to GND)

Chip control (voltage):

TDA8566:
Standby - 0-2 V
Mute - 3.3-6.4 V
On - 8.5-supply voltage

TDA8595:
Standby - 0-1 V
Mute - 2.5-4.5 V
On - 6.5 - supply voltage

Chip usage (all in analog control mode):
TDA8566 - FL + FR chanels
TDA8566 - SW (PBTL mode)
TDA8595 - RL + RR + Center speakers

When I used beeper, both 66 chips have mode pin conected to GND (Standby mode). But I don't know if directly or thru some transistors (hope so), becouse lines are hidden under chips. 95 chip have line from STB pin to transistor area in top left corner of PCB.
Solving could be cut MODE/STB lines and connect them directly to Amplifier enable voltage pin. Problem is about 66 chips, which have lines under them, so for setting solid "ON" state you must desolder them and then solder them back.