John Deere CommandCenter will not start anymore

[Aheld]

Hello,
may be someone can help?

I have a defect John Deere CommandCenter device which will not boot anymore.
I already found out that the enable signal for backlight stands on low, so display is dark. If I connect a high level to this pin, backlight starts, but screen don't show any information.
So my guess is an issue in controller part.

Some additional observation:
- Supply voltages are available (12V input and at ignition PIN, 5V, 3V3, 1V8)
- only the upper CAN controller has a running oscillator, at lower CAN controller, the oscillator is not running.
- Device of realtime clock has no supply and seems to be switched off. The Oscillator is also not running.
- Current consumtion is approx. 230mA (instead of approx 600mA for running device)

1) does anyone knows this issue and has an idea how to fix it?
2) Most of the devices are identified, there is one device close to powersupply, I can't find any information pictures are in the attachment.

Does anybody know this device? Or can help?

Thanks in advanced
aheld

[Stray Electron]

  I can't help but there are so many of those out there that I would think that someone would have started developing 3rd party support and 3rd replacement parts for them.

   NONE of the farmers in my families would ever have bought such a gimmicky farm tractor. They want ultra simple and reliable equipment that can be fixed with nothing more than a screw driver and a monkey wrench! My cousin is still using the MF tractor that his father bought in about 1970 and the Ford 8N tractor that he bought when he came back from WW-II.

[Gribo]

Since you mentioned RTC, Is there a battery on board? Coin cell? Lithium primary?

[amyk]

That is NCP1406SNT1G.

[Aheld]

@ amyk: Thank you very much. You're right this is the device and works fine after pulling enable signal to high.

Meanwhile I was able to start the device a couple of times, after oscillating the ignition signal at the connector. But this is not stable and really random.
I think a central switch-on signal is missing. If this will work, I'm currently quite sure that display will work again.

Close to the Step-Down Controller (TLE6389) is another decive I can't identify, because of too many possibilities (Marking W3P).

Does anybody knows this device?

@Gribo: no there is no battery implemented. Meanwhile I think there are some configured funktions which are switched off, like second CAN Interface
@Electron: I aggree with you, but I'm the guy in this village who knows how to work with an oscilloscope. So I'll give the display repair a try 

Thanks
Aheld

[xavier60]

That behavior could possibly be caused by an inactive crystal resonator. It's usually possible to probe one side with a X10 probe without stopping oscillation. Also note the DC voltage on both sides.

[Aheld]

The oscillators looks fine (frequency and amplitude)
I collected some information in the attachment.

After connecting ignition voltage at bottom connector, the main 5V supply (upper left corner) starts working, also 3V3 and 1V8 supply.
I'm still wondering about the "W3P" device and funktion of the TL072 device.

Does any body knows if there is a schematic available?

Thanks
Aheld   

[xavier60]

The CPU Reset line should be checked also, but how to find it, I don't know. It might even involve the mystery IC,W3P, or the TL072 opamp.

[gamalot]

Does anybody knows this device?

https://pdf1.alldatasheet.com/datasheet-pdf/view/86162/ONSEMI/MC74VHC1GT126.html

[Aheld]

Hello gamalot,

many thanks.
Did you know the device or how do you found it?
Only google didn't help me.

[Manul]

What about TPS3103? It has power fail input and output and reset output. Some interesting signals. Maybe that reset is used alone or in combination with something else as CPU reset? Is there external watchdog present by any chance?

[gamalot]

Hello gamalot,

many thanks.
Did you know the device or how do you found it?
Only google didn't help me.

Sometimes when identifying components, searching in Taobao is more effective than Google.

https://www.taobao.com/

[joeqsmith]

Is the dealer unable to get a replacement, or is the tractor already repaired and you are just trying to fix this one for a spare?   Does JD offer a repair service?

I am going to guess with the wide temperature changes, vibration, lead free its a solder failure with the BGA.

[cemelec]

JD are not big fans of the Right to Repair movement, an attitude  enforced on their dealers. In fact, if they could get away with it they would probably sue you for attempting to repair your own equipment.

[LECKO]

Funny you should say that, they tried and lost a case, I think the court told them that when someone buys a product, that product is the buyers product, not JD's.

Most new tractors of all makes and colors now have high end electronics on them, Kubota's on all the HP's over 25 now have complicated emission controls, and take it from me, they can be pigs with error messages.

[Aheld]

Currently  I‘m waiting for some device delivery, in special devices which becomming hot while working. Let‘s see if it helps.
Meanwhile I also found a strange behaviour in 5V supply. The measured resistor of supply net is approx. 40 Ohm to GND. Independant of measurement polarity. For me it sounds a little bit too less. The Tantal Elkos are still good. 

So still my question to the forum. Is there anybody who can help with a schematic? Or only a snippet? Maybe as PN?

[Aheld]

Hello forum,

I'm currently trying to order the NCP1406SNT1G switching voltage regulator.
It is really hard to find, because it seem that there isn't any stock of this devices.

Does anybody knows a selling point in germany or maybe any replacement type of this devices?

Thanks
aheld

[wraper]

Hello forum,

I'm currently trying to order the NCP1406SNT1G switching voltage regulator.
It is really hard to find, because it seem that there isn't any stock of this devices.

Does anybody knows a selling point in germany or maybe any replacement type of this devices?

Thanks
aheld

Just get it from some dodgier place like Aliexpress or Utsource. There is nothing wrong in buying parts from those kind of places when there is no other choice. Just don't buy jelly-bean things like transistors since chances of receiving counterfeits will increase by an order of magnitude at least.

[fzabkar]

Did you know the device or how do you found it?

http://www.smdmark.com/en-US/search/code?id=dam
http://www.smdmark.com/en-US/search/code?id=w3

[symp]

Is the dealer unable to get a replacement, or is the tractor already repaired and you are just trying to fix this one for a spare?   Does JD offer a repair service?

I am going to guess with the wide temperature changes, vibration, lead free its a solder failure with the BGA.

You are correct. 5000+ hours of heat cycling and vibration is my guess. I have 2 sitting here with bga solder failure. Unfortunately it's a 324 ball chip with no stencil readily available for reball, there may be a universal that works, I would love to find it. Anybody want to reball for me by hand? 

LH7A404 chip, with silicon underfill, making a simple reflow next to impossible. Only option is a reball or NOS replacement.

[Aheld]

Hi Forum,

after several private posts, I restarted investigation on JD command center.
As you can see, my test setup is that one side of the PCB is lying on the frame of the display to have a chance to put some pressure to the big BGA chip (CPU).
Putting some pressure to the PCB and then connecting GND, VCC and Ignition to the PCB let my command center start.

From my point of view, I'll try to resolder CPU device.
As preparation, I'll order a solder paste mask for the BGA and then unsolder ==> reball ==> solder the CPU device and hope that the issue is gone.

Br. Axel

[Aheld]

Hi forum,
I‘m going to do the first resolder test of the control IC.
Currently I‘m wondering how the coating will react with the desoldering process.
I tried to remove the coating best as possible from PCB and IC, but realized that some of this material is also under the IC between the solder bumps.
So I can‘t wet the existing connections with flux.

Is there any idea how to move forward?
Is there any idea how to wash the coating away between IC and PCB?

Br.
Axel

[Aheld]

I started with de soldering the Controller.
First I remove much as possible of the coating with a little knife.
Also under the IC until first solder bump row, with the hope to get a little space for the flux that hopefully easy heating up is enough to fix this issue.
After heating up some solder tin swelled out under the IC, which means for me that the coating is expanding with heat.
Not good :-(
So I unsoldered the µController.
The coating was completely under the µController. Very good from point of production! Not really good in my situation.
Next step would be to rebump the µController and resolder it. Lets cross the fingers that it will work again :-)

[Gyro]

It looks as if you've torn off a couple of pads on the underside of the BGA package.

[Aheld]

Yes, but I had luck. These are only pad‘s and not connected.