​​​​​​if you have cold feet you can stay with exactly 3300uF/25V and bump the voltage even greater than 25V to a physical size that still fits the available PCB space.

The 16V insulation is what's short lived in 14.9V cars. Damaged caps leak DC current into tiny speaker coil...

 

I ordered and received the 25V 4700 uF capacitors. I’d have to order and wait for 3300 uF capacitors if I went that route. In your opinion, is there a risk using 4700 uF and if so how risky would you say it is? I’m a mechanical engineer, so I don’t know enough about circuits to comfortably make the decision.

 

this upgrade is far better than what you are replacing because of added operating margins. The jockers that spec'ed 16V caps knew what chaos they were after...

These basic audio capacitors have been around since 1950's... AC/DC audio couplers are not mysterious: they conduct the AC and block the DC.

Fear not... but be sure to match the orientation of negative (-) polarity when soldering these caps and use heatsink paste where spotted on the hot chips.

+++++ 3300uF vs. 4700uF ++++
> Using a higher capacitance value helps conduct wider frequency band with more plates surface.

The larger cap is a bit stronger with no downside for that improvement besides physical size.

> The premature failure is from low insulation voltage having no margin. Caps have operating life after that the failure rate goes up. Anything better than ridiculous 16V is an improvement !!!
✌️

 

with capacitors, higher voltage rating is always safe. different capacitance values may or may not be an issue, depending on the circuit. large capacitance values like3300, 4700 are usually used as noise filters. to smooth out the power supply, so larger just does a better job up to a point. downside, larger caps are usually bigger and may not physically fit in the available space.

 

I installed the new capacitors (25V 4700 uF), disconnected the specific center front speaker wires as suggested, and everything is working like a charm. Note: The new capacitors are much taller so I had to remove a lot of material from the amplifier aluminum cover using an end mill and drill press. I appreciate the help and suggestions! Saved a lot of $$$

 

Give yourself a big hand - Glad you can enjoy a great car with smart savings.

Another ounce of prevention: use your "WORKSHOP" menu display to monitor what your car charging system us up to.
Hopefully you do NOT see low Volts (<12.2) and high Amps (>15A)...
🤞

 

I am having the same issue but for my front center console speaker. I have disconnected the speaker fuse and the popping noise has stopped. What would you recommend first? Any help is appreciated. Thanks

 

You have done step 1 already by removing power

Step 2 is to fix your amp capacitors

Step 3 is to compare ohms of popping speaker

> Quick shortcut... fix NOTHING!
Simply cut one wire of the bad speaker directly at the amp. It's a very easy access. You could pop the speaker out of dashboard top to unplug it.

Popping sound is gone, right?


​​​​​​

 

Thanks for the quick response. I am a newbie to MB, so please ignore my ignorance. What if I just unplug the front center speaker, since I have no use for it. Would that solve the issue? I don’t wanna mess with the amp. Thanks

 

speaker popping and crackling is almost always an amplifier problem. a mechancial problem with the actual speaker is usually more of a buzzing or distortion thats quite consistent with the sound content and most noticable on bass hits. an electrical problem with the speaker itself is almost always works or doesn't work at all.

 

yes, very true!

It's good to keep in mind the difference between an abused speaker coil vs. a bad amp sending garbage pops into one or more speakers.

 

I really appreciate this help. Is there a way to tell which wire is associated with what speaker on the amp, so I can just disconnect that. Thanks

 

You are dealing with dashboard center, right?

The fastest and easiest is to unplug spk from there. Pop the grill, unplug connector, done.

Else you'll need a schematic for your VIN then match colors etc

 

Yes, it’s only dashboard center speaker. I will just disconnect the speaker, I will keep you updated. Thanks

 

Yes nice and easy.
No need to stay in the service line now.
Happy 4th O'July to you 👍

 

I was finally able to get a chance to remove the front speaker cover. I was able to locate the sensor plug but I can’t seem to find the plug for speakers. The location of the speaker also makes it challenging for me to look around. I am just sticking my hand down there and can’t locate any wires to unplug

 

It's difficult to see anything in that location so take couple pictures to help you make out what's going on... I bet your iPhone comes with a camera, yes?

 

https://mbworld.org/forums/e-class-w...ml#post7427738
https://mbworld.org/forums/e-class-w...2014-w212.html

 

I was actually able to pull out the speaker and then unplug the wires. Everything seems to be working fine now. Hopefully my other speakers don’t end up like this. Thanks for all your help

 

Questions, how many capacitors need replacing and what size (diameter/height) did everyone get that fit without modifiying the case?

Thanks,

 

Any chance you can contribute your time with this cross-referencing?

When do you need an improved replacement ?

 

Just got my E250 a few days ago, been reading up on everything that I should take a look at and wanted to head off the issues some describe here. Dont necessarily need a improved replacement soon but was thinking of ordering the caps so that I can modify it when time allows to prevent any issues down the road.

When I was looking on Amazon I noticed that of the 3300uf 25v caps there were a few what I assume are standard sizes. I have not taken it apart yet to count/measure and would prefer to have parts on hand prior to dismantling so I can accomplish the task the same day.

I are mechanic in previous life but I can solder and apply thermal paste good enough.

 

Here I found my pictures of this module... enjoy

overall circuit board

caps values

caps markings

proprietary Amp chip

We don't have the internal schematic diagram... until someone finds it.

My failure analysis done by experience.
The parts count now makes me doubt these amazing 16V caps are inline with line outs... they must be just filtering the ripples over 14.9V power and die on the job.

We want shorter ripple spikes and higher voltage to limit premature damages in a package that fits the enclosure.
✌️

 

Interesting, judging by the pics the ones I picked up may be a tad too tall. Got the shortest ones I could find on amazon (quick search) 16x25mm I believe. Wasnt much money wise but may have to look for some shorter ones.

Did a quick search for that 7575b chip looks like you can get them off ali for $1 or amazon for $11. Seem to be standard audio/amp chips but no idea on the programming (if required, previous mechanic here). Ofcourse changing those out is kind of difficult due to the soldering technique to get all those little pins done right. Someone with experience not to bad.

 

Thank you @Quint22 you are a very good man!

chip typical application

We now know a whole more than 10mn ago... the outputs are direct coupled without any cap but the INPUTS are decoupled by .22uF caps (what voltage here?)

The application sheet specs 2200uF per Amp to clean the power supply. We got 10000uF (3300uF +/-20% in parallel) for 5 chips.

So we got more answers and more questions! At least we can do bench troubleshooting with a diagram now. Thank YOU!✌️