Neumann KH80DSP Teardown

[randomusername]

If they break down during the warranty period, then Neumann is only taking themselves for fools.

If they break down right after the warranty period, that's skill.

So my KH80 has refused to turn on today , just half year after warranty end date. Power LED do not lit. Intending to disassemble it and check those trash neumann capactiors you guys were talking about

 

[iamrackman]

Hello everyone! I have been visiting and reading the forum as a guest for years but I have decided to make my first post.
By the way, what you guys do is great! In the end.

Unfortunately, one of my KH80 AG US studio monitors is malfunctioning. It lights up, the LED goes from red to white, OK, but then starts making strange noises or nothing.

These were won in a Neumann mixing competition in 2023.
The firmware is at the latest version: 1.3.6

Things I tried:
I changed the power cable.
I tried different electrical outlets.
I tried in different rooms and at friends' houses.
I did a factory reset.
I tried with Cannon cables, Plug cables, and no audio cables.
I changed the local setting to network.
I used MA 1 with its corresponding microphone.
I took the device to the authorized technician in my country (Argentina) (I waited two months, and they told me there was nothing wrong with it).
I spoke with Neumann agents.

None of them were able to give me a logical and accurate answer.

Any ideas? Sorry for my english

Video link

 

[AnalogSteph]

I took the device to the authorized technician in my country (Argentina) (I waited two months, and they told me there was nothing wrong with it).

?!

Your problem sounds like a pretty hard fault, I don't get how it could turn into a no fault found elsewhere. Unless... is your location particularly hot, cold or humid by any chance? Or does your mains voltage have a habit of going out of spec? Obviously this may simply have been the service center's way of load-shedding, in which case you would simply have been lied to.

Had a look at the video... that's wild. Since you can apparently provoke the most random behavior by momentarily turning off/on the power, there are two avenues I would want to investigate:
1. The power-on reset circuitry for the DSP section. It almost seems to me that the unit often powers up in an undefined state. Could be a pesky little SMD electrolytic capacitor in the delay that's called it quits.
2. Stability of digital power supplies.

You need a good, reliable electronics tech who'll work on modern(-ish) electronics with surface mount components, and ideally a service manual (no clue whether Neumann would provide it to you, but asking won't hurt). You have been given the runaround for way too long.

 

[iamrackman]

?!

Your problem sounds like a pretty hard fault, I don't get how it could turn into a no fault found elsewhere. Unless... is your location particularly hot, cold or humid by any chance? Or does your mains voltage have a habit of going out of spec? Obviously this may simply have been the service center's way of load-shedding, in which case you would simply have been lied to.

Had a look at the video... that's wild. Since you can apparently provoke the most random behavior by momentarily turning off/on the power, there are two avenues I would want to investigate:
1. The power-on reset circuitry for the DSP section. It almost seems to me that the unit often powers up in an undefined state. Could be a pesky little SMD electrolytic capacitor in the delay that's called it quits.
2. Stability of digital power supplies.

You need a good, reliable electronics tech who'll work on modern(-ish) electronics with surface mount components, and ideally a service manual (no clue whether Neumann would provide it to you, but asking won't hurt). You have been given the runaround for way too long.

Hi @AnalogSteph,

Thanks for taking the time to reply. To give more context, the monitor (currently the right side) was working perfectly until 3 months ago, then these strange noises started.

My studio isn't hot, humid, or cold. The left monitor actually works perfectly.
I've tried other power outlets, and they reproduce the same error. I'm attaching a screenshot of my UPS, which they're now plugged into.
In my opinion, I don't think the problem comes from that side. I've also used two monitors at my friend's studios and a friend's house.

I have other monitors available in the studio, and they all work perfectly; of course, they don't have DSPs.

What you said about the SMD capacitor seems more logical to me.

Unfortunately, the official Neumann service center in my country "didn't detect a problem with the monitor," which seems like a joke to me.
Honestly, if they didn't "see anything," I don't really know what to think. I also imagine they didn't open the monitor.
I'm afraid to take it to a non-official service center, even though I understand the warranty must be expired.

I've written to Neumann again, but their responses are silly. I imagine Neumann has never had a case like this.

The situation is truly frustrating. Is it a poltergeist case?!

Other video: https://drive.google.com/file/d/1SrZR8ruyMQPhN2QbIvOAmAO-Kxcv93Nb/view?usp=sharing