BMW OEM Amplifier 9 264 953 – Help Identifying Missing SMD Component

[Doyle1]

Hi all,

I'm currently working on a BMW OEM amplifier, part number 9 264 953, taken from a 2011 BMW F10 535i.
There's visible PCB damage near the NXP 74HCT193 chip, where a small SMD component is missing or burned. Based on shape and size, it's most likely a ceramic capacitor or resistor in 0603 package.

I recovered the loose component (appears unmarked, like a ceramic cap) and have detailed photos:

– PCB with missing part
– Close-up of recovered component
– Full view of the board

I'm looking for:
- The correct part type (capacitor or resistor)
- Value (if known)
- Help from anyone who has a matching board or schematic

Thanks a lot in advance!

[CapLeaker]

The damage is on the VCC pin. So the black burnt looking SMD can't be some higher ohm resistor, rather a jumper or a ferrite beed etc. Looks like the damage went also to the D0 dataline and MR master reset pin. Check that small MLCC cap above that burnt black thing to see if there is a short or not. You may need a new 74HCT193 too.

[Doyle1]

Thanks a lot CapLeaker for the detailed explanation – much appreciated.

Your analysis makes a lot of sense. The damaged area is indeed on the Vcc trace, and the missing component looks like it could have been a ferrite bead or jumper.

To add more context: the amplifier produces sudden, loud "pops" or "bursts" in all speakers at once. Sometimes this is accompanied by high-pitched whining or squealing, and then it goes quiet again – only to repeat randomly. These are not soft clicks – they are full-volume spikes, as if some power rail or logic state violently flips.

There are no signs of damage in the output stage itself. It's as if the digital control logic glitches and sends full signal bursts to the output stage for a split second.

Would you say this behavior is more likely caused by unstable logic Vcc, or could a faulty 74HCT193 chip itself generate these erratic outputs even if Vcc seems OK?

Any additional thoughts would be extremely helpful – thanks again!

[CapLeaker]

The 74hct193 is nothing more than a digital synchronous counter that can count up and down. My best guess it is used in this amplifier for gain / volume control or digital gain control… something along this line. Maybe balance too

[lotas]

Most likely, moisture got into this area or electrolyte leaked from the back side, if it is there, this power supply chain of this chip is a blocking ceramic capacitor, a choke and again a ceramic capacitor, wash this area with a toothbrush soaked in isopropyl alcohol, a little lower also on the terminals of one oxidation controller...