Occasional thumping noise from speaker

[Willygee]

Best to describe noise as a large bird dropping hitting the roof but coming from the speaker(passenger side  top of dash) typically after just starting the vehicle or shutting it off. Radio off only. Normal radio CD operation at this time. Van does have shore power battery charger AC inverter and accessory USB ports as well but these have been installed for several years now without issue but could be a factor. Suggestions appreciated.,

[mculbert]

There is a common issue with these Ford CD radios, once they are a few years old. The electronics are similar across Transit Connect, Focus and Fiesta.

 

Behind the button panel/readout (where the CD goes in) is the audio hardware. Inside the unit, the block of the two amplifier transistors (left and right) are fastened to the metal case of the unit via screws. This allows the metal case to act as a necessary heat sink, as they generate heat during operation, and excess temperature will destroy the transistors.

 

There is a thin layer of heat sink compound between the transistors and the metal case, to improve heat transfer. Over time, this dries out, which tends to cause it to be an insulator. This causes overheating and weird noises from the speakers.

 

If you are handy, you can open the dash, remove the unit, open the case, clean off the old compound, add new compound and re-assemble.

 

This compound is common stuff, same as used for computer processor heat sinks. It's inexpensive and you can find a tube at Best Buy, Amazon, etc. You want a thin, even layer for best results.

 

On my 2012 Focus, I was not able figure this out before the thumpy noises became extremely loud, constant and the transistors were destroyed. On my daughter's 2011 Fiesta, I was able to successfully fix when the problem first started, and she's had no issues since (been good for something like three years).

 

Hopefully I haven't over-explained things, I just wanted to have the full info out there for anyone on the forums going forward.

 

If you try the repair, let us know how it goes.

Edited December 3, 2022 by mculbert
grammar

[Willygee]

Appreciated...something i may tackle if it gets worse. I have heatsink compound at the ready.

[Don Ridley]

I looked inside the original ACM from my 2016 TC. Here are photos of the ICs that that are attached to heat sinks. I don't t know their exact function but they are probably op-amps or other amplifiers for the 4 channel outputs. The ICs are connected to the heat sink by the two black screws. The heat sink paste was is good shape on this ACM. I added some more and re-assembled. 

 

If you need a 4 channel / CD ACM, I'll let you have this one cheap. It works fine and I replaced it with one that had HD radio.

 

 

 

[Willygee]

Good to know. All behaving at present but when hot summer sun arrives hear in Florida..probably a different story.Don's spare parts may be needed.

[Willygee]

Speaker thumping still just occasional.. before I buy Don's ACM and have to take everything apart is there a fuse or wiring circuit that would just disable radio and or just speakers ? Added note... thumping may not be heat related . I went to the truck the other day to get something out and when I closed the door I heard the thump or pop. Vehicle had just been sitting ..no keys in ignition no radio on...I dunno ?