CaliBenzDriver

Happy to read you are gaining traction: your angel is working OT for you 👏

This sounds like an oxidized wet carpet GND improving with sunshine.
Why is that... because bad electronics does not radically improve from bad to good. Soft-crash does become temporarily perfect after proper reset or battery reboot.
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CaliBenzDriver

How did we go from "NTG Surgery" to "Carpet GND" ? We shifted the order of importance.

We made and educated guess on what the problem most likely is based on evidence. Besides we already know the way amazing GND are built.

Now the order becomes:
1 NTG GND at front footwells ..
2 NTG surgery ..
3 Disturbed network CAN/MOST ..

✌️

ArchAngel2190

Yep, although I was going to take a gander at that driver footwell ground anyway since it's $Free.99 and that's my favorite price. That's my task for today but I should confirm... I've been browsing this thread thread and came across your post noting this ground, is that the ground in question here?

CaliBenzDriver

Good find!
​​​​​​​Where you see @S-Prihadi ... are usually excellent learning topics and well worth your time to dig in.
Some of us understand how small details are seeded all over the place to snowball into amazing opportunities.
"Painted GND" posts are a perfect example used to introduce power glitches into sleepless crazy modules.

​​​​​​​Feel free to search "Old" threads and extend them as you see fit - Good stuff is timeless!!

ArchAngel2190

Indeed indeed. Well, I pulled apart the driver's footwell and inspected that ground. That process was a lot more involved and much sweatier than I anticipated. The ground showed a little corrosion, likely on account of all the salt that has been tracked in over the winter (seems like a great place for a ground...) and thus I cleaned it thoroughly, but alas to no avail, as the radio still exhibits the same symptoms.

For reference, here is the state of the complaint as far as I'm able to discern:

- The radio does not start when the car is cold started.
- The radio may (or may not) start up eventually after driving for awhile (15-30mins or more).
- If/when it does start, the radio is finicky - seems anything (or nothing) will cut it back off, but once that happens it almost always reboots and once it has done that 1-3 times, the radio becomes "stable" and doesn't power off.
- The longer you drive the car, the more stable the radio gets, it seems. If the radio boots and then 5 mins later you go to park, harsh steering movements will cut it out as will turning the engine off (it dies immediately).
- If you drive for 15-20mins with the radio operational, moderately harsh steering such as while parking will NOT turn off the radio, and when turning the car off, it will stay alive for up to 30 seconds before dying out (as opposed to instantly doing so).
- Battery, alternator, voltage regulator are all new or close to it, and the footwell ground has been cleaned.
- Radio has showed progressive decline in serviceability since initial presentation of the issue, though sometimes that decline inexplicably reverses or plateaus (not sure which) and the radio seems to work as described above (as opposed to not working at all like it had been the last couple weeks).

Below are some (needlessly quite large) photos of the driver's footwell ground as I found it before cleaning it... is it time for disassembly? It really feels like a power issue to me but whether that power issue is internal or external I do not know. With every hapless repair that I perform without positive results, my bridled rage becomes ever so slightly less so. Lol. I am slowly (but very, very surely) being driven absolutely mad by my inability to diagnose this issue properly. I take solace in your assistance and the notion that in some way or another, we are making progress.

CaliBenzDriver

oxidized GND lug

That's half the battle....
The part that is "painted" is the nut side. Have a look at it: it has a lip of paint all around that prevents it's contact.

Make sure batteries are disconnected during GND rework.

ArchAngel2190

Wait, the NUT is painted? WHO THE **** PAINTED THE NUTS!? (Hah. Nice.)

Damn. I didn't even think to clear off the nut, although the nut just holds the ground to the actual ground post, yes? Would having the fastener to the ground post have paint on it be an obstacle if the ground connection is made properly between a clean and dry ground post and eyelet?

Also, note numerous edits to the prior post.

CaliBenzDriver

I recall there are at least TWO GND posts on driver side. Actually 3x posts as one post was originally left unused.

Each post has multiple connections gathered into a sandwiched stack that must be clean to conduct with low resistance, plus the TOP NUT itself.

Hopefully you did have battery out during GND, else dona battery reboot now then scan for active faults.

Having good GND is not an option, it's a requirement. Even if that does not directly yield concert hall results, the F-SAM VIP module benefits as it GND at driver footwell.

CaliBenzDriver

thick paint layer

Paint pretty much guarantees you only get half contact surface on GND posts

Can you guess what color is my grey car

The good thing with this thread is we are likely gonna put the NTG BS all the way to rest step by step for 10¢ !


++++ RAINBOW nuts ++++
Can we build a collection of our carefully painted GND nuts with every MB car colors ??

That would be a good lookin' MB Rainbow for "precision crafted" advertisement.
✌️

ArchAngel2190

As much as I'd like to add to the rainbow, my car is wrapped up in that beautiful tenorite gray metallic (Tenoritgrau mettalisch) so I, too, will be in the grey category.

I still don't know if I believe having paint on the nut side would create such an issue, but it costs me nothing to try. Have you seen that nut having paint on it cause issues like this in the past? Also, is there an easier way to access that nut without having to hold the 50-ton carpet back with one hand? I can't get the carpet down around the brake pedal, so I'm stuck hauling back on it and wedging a light in there so I can see. Worked up a hearty sweat doing that yesterday, so I'm looking forward to doing it again today...................

While I'm in there, are there any other grounds to which I ought to pay attention? You mentioned there was another one in there somewhere. Also this time, I will disconnect the battery. Totally slipped my mind last time.

ArchAngel2190

Alright, just cleaned both the drivers footwell grounds with no success. The paint rim you mentioned was present (see below) so I cleaned that and also cleaned the post, nut, and all the connections on the lower ground.

With every unsuccessful repair, I can feel my bridled rage slowly becoming less so… 😭

CaliBenzDriver

Long story short: now either research blinking codes or extract NTG for invasive surgery

I have a hard time understanding how the unit can work almost reliably sometimes and refuse to work other times. That would seem consistent with networking issues preventing NTG from booting/initialising normally (security check the VIN across CAN
We have no car faults... meaning all modules are concidered working well.


Fixing the integrated NTG: it uses car data streams to work (steering buttons etc...)

Layered causes of randomness: process of elimination!
An oxidized GND post fastened by painted nuts feeding power though loose pins to a state of the art module with under size riple filtration.
(This is the equivalent of Mercedes fastening the engine heads with not enough under sized soft alumium bolts)

Many known factors are deployed to help crash MB modules when very few factors compete to help troubleshoot issues efficiently.

No live DTC faults reported comfort us to point a bad module

Poor GND opportunities need to be made reliable to prevent stressing module with glitchy power supply

Voltage measured remotely... part of ALT voltage control is done by R-SAM away from Eng. GND (WTF cable voltage drop)

Blinking code reference, no DTC: NTG acts as the MOST controler and gateway to busy CAN-B with buggy peripheral collection (EIS, KG, DCU..)

​​​​​Testing on-screen watchdog: when unit is functional there is an opportunity to gently tap around the unit front...


Invasive surgery to visualise if indeed an electronic weakness was planted in NTG module. May or may not help, I do not know this internals


I can attest that when powering up my car, my NTG plays radio even before screen display finishes booting logo.
It used to be somewhat slow until I reworked my SCM, EIS. At that time I already had good CAN-B peripherals and reworked my rotary dial knob.

At this stage I would personally consider unboxing NTG ahead of considering dealing with CAN partners.
My NTG works well, however if proven junko I may rework that unit at some point.

(Don't overlook to clean the air filter of your NTG dedicated blower fan. It helps offset 200F heater core)

ArchAngel2190

I'm not sure I'm following your last post. We're into invasive surgery since I cannot find ANY information (in WIS or on forums) on the blinking radio light.

I think you're right about the networking issues, but I don't believe I have the tools to check that.

Both the grounds are good, and there are still no DTC, even after a battery reset. Voltage measured through the diag screen on the center console is good. When the unit is functional, I could try a system reset on that, but I haven't done so as of yet. Next time I can get the radio to boot up properly and hang on for long enough, I will try that. Other than that, and barring the dealership finding anything when I take it there next Monday, it will be either an invasive surgery or a replacement. How involved is it for the dealer to reprogram a radio to my vin? Since I do not have Xentry, that's not something I can do myself. Any idea what the dealer might charge for that?

Current course of action:
- Ask the dealer to take another look at it next Monday and get their opinion.
- Remove and attempt to diagnose/repair NTG module, else;
- Replace NTG module with a used one and have it coded to my car.

CaliBenzDriver

I don't think MB dealer is going to get involved with any 2nd hand unit. They are the main provider of OEM parts. Parts are built such that they require service. The day when troubles come you can't get away without paying for excellent service.


Plan B for DIY'ers is to deal with parts themselves.

Some people can deal with electronics, some prefer to send out their unit to an Internet repair shop.
They usually offer some form of Plug'nPlay. Either your very own unit is doctored -Or the 8-pins E2PROM ID-chip is moved over to a donor unit that then appears identical to yours.

Mercedes modules are built with standard Easter Eggs easy to deal with early on.
Ex: the W212 premium digital fiber sound amplifiers modules use heatsink and fans for cooling. The OEM thermal compound evaporates so you're left with roasted chips if not maintained before failure. Easy to repair because MB are built to be serviced.

ArchAngel2190

Here’s a thought I’ve just had.

I reset the radio to factory. Things seemed to get a little better. But then I tried to save my SXM presets and when the radio inevitably restarted, they weren’t saved. Then I got to thinking.

Could it be that the hard drive is going bad? As we’ve now determined, battery voltage and current fluctuates with big draws like the steering. It also fluctuates with accelerator input since it’s TBW. It also fluctuates with engine shutoff via ECO. A healthy drive would not care about this but one with failing internals would have low tolerance for voltage fluctuation. Additionally, inability to write data could be another side effect.

Thoughts on my theory?

CaliBenzDriver

I like it a lot!
You're thinking it maybe the cheap internal HDD spinner that's going bad or the boot record that's corrupted...

We can take the disk out to read the self-checks registers, run error checking scan and a defrag... image the HDD over to a perfect 256GB-SSD... experimental.

In the end, it will be interesting to figure what they've got cooking.

> MOST Ring deal:
As far as i know when any media unit in MOST goes bad it cuts out the fiber ring - The digital input amp then stays silent by lack of streamed data


> GREAT!
The digital sound system in these W212 is the cleanest I have ever heard.

Each speaker transducer uses a dedicated amplifier channel. There is coil and cap crossover that dampens output response sound.

Everything is data driven by fiber channel, DAC Converters, DSP Filters... just the way a computer geek likes it! Danke schoen...

ArchAngel2190

Alrighty, so I took the car to the dealer again for a steering recall, and while there I asked them to look into the radio again. Below is verbatim what they wrote on the service invoice:So it looks like it's definitely voltage-related. How can we test the command unit wiring?

CaliBenzDriver

This pretty much rules out external issues and squarely points at NTG coms.
Here is my between-the-lines translation of dealer language: "wiring tested" ... means check for bad GND or poor connection from non-soldered pins.

The harness itself is static and is away from the rain intrusion path... it is 99.9% good

The unreliable NTG unit itself is not totally stuck. It is running and able to issue self-diagnosis fault codes.
This is consistent with poor connections created by solderless assembly. Imagine each pin of every connectors inside the unit being sensitive to humidity and vibrations... that's a lot of opportunities for failures. Some of the other modules are built to be reliable such as NTG Display screen and Instrument Cluster are good guys.

ArchAngel2190

OK so sounds like we have a nearly definite answer here. Is there any pictures of the connections you're talking about? Just so I know what to look for. I will probably pull that unit this afternoon.

Left Coast Geek

I believe they are referring to the innards of the COMAND head unit, every circuit board in there is going to have stuff that's pressed in but not soldered.

CaliBenzDriver

Let me help you save your time when disassembling your COMAND box:

> NUMBERING loose SCREWS :
1-- Print a pictures of all sides of NTG 2-- Use a strip of masking tape to seeve as header for piles of small chassis screws. Number the headings 1234...

3-- Remove screws to open the NTG.

4-- Deposit each screw with like sizes

5-- Note on the paper picture the heading No.

You'll need that chart reference for quick reassembly else impossible with 5 different screw types.

Post pictures of your circuit boards. In particular the solder side of connector... opportunity hidden in plain sight when you know - Who knows really, no one has been inside this unit

ArchAngel2190

I'll get to it! Hopefully tomorrow. Started this afternoon and spent the entire time ****ing up the interior trim trying to get it off so I could access the radio in the first place. Even tried following AR68.10-P-1180EW "Remove/install trim strip on dashboard"....

Will give it another go tomorrow. Any tips for impromptu tools to use for that passenger-side vent? I don't have tool 140 589 02 33 00 "Pulling hook."

CaliBenzDriver

hand held pick hook

you can use anything shaped like a hook, a tool or a section of clothe hanger bent to shape.

ArchAngel2190

Alright so after causing a bit of damage courtesy of some very very fragile plastic on the back of my trim, I was FINALLY able to remove the unit and begin disassembling. Or not - I have removed every visible screw and then some from this pile of **** and I cannot seem to separate the metal coffin it’s encased in!! I have taken out all the 5 different types of screws in the outside of the unit and have also removed the hard drive and front auxiliary button fascia. What the hell am I missing??

Photos attached.

CaliBenzDriver

Regroup, don't back down brother!
You're almost in there.
​​​​​​

Snaps built

You are Indiana Jones getting in... this unit is not buby trapped .

With all the screws removed, now it must be the outside parts are just snapped together.... nothing too serious.