Today at Atelier Kaz - ex-Honda R&D, F1, Indy/CART engineer

While working on the Door Glass Refresh, I was servicing the door AMP for another owner.

He told me that after about 5 – 20min using the audio system, it will start making loud popping noise.
Typical capacitor leakage so thought it’s going to be an easy fix.




On initial inspection, there was trace of someone re-soldered one of the FET but nothing else and
while all of the capacitors were old spec, there was just minor leakage around the big caps and no major leakage that reached the IC areas.



Before removing anything, quick measurement on the bench and it was safe to power it up so started the initial testing but
even after driving the AMP for 30min, still no popping noise….
There was minor hissing noise in the background which is normal for any AMP with leaky caps but not that famous really loud popping noise.


Kept driving the AMP for over 1Hr but still no noise so at that point, stopped the initial testing and started removing the caps.




As expected, big leakage at the bottom of big cap C18 & C19 as well as C7 & C8 but rest of the area was not too bad.




Cleaned the board, strengthen the damaged tracks, replaced all Al caps, applied hot melting glue and quick bench check.




Happy with the result so applied conformal coating and the thermal transfer compound.




As I couldn’t re-produce the popping noise that the owner mentioned, kept driving the AMP for 5.5Hrs including thermal shock condition.
No noise at all so happy with the result and done.




About to return the AMP to the owner so hope he can test this on his NSX.

If the owner gets the noise again, I’m afraid it’s more likely to be audio head unit issue or something outside of the AMP unit.

Thank you for using my service and please keep me updated with your audio status.

Regards,
Kaz