Kenwood DNX6990HD service manual needed

[tibimakai]

I have picked up one of these from craigslist for cheap, but it has some issues and missing parts.
It's in a reboot loop mode. It reboots with the Garmin screen. Sometimes It boots up to the initial setup screen.
I have unplugged one of the ribbon cables which I believe is the Garmin unit(not sure though) and after reconnecting it and powering up the unit, it booted as it should to my surprise. I have done all the setups and it went to the home screen. I was happy, but as soon I hit the nav button it went back to the reboot loop again.
First of all I need the service manual to make a USB harness which is missing from the unit. It should be a hard wire harness, but it's missing, weird. It's not really hard wired, it has a four pin small PC like connector at the end.
My problem is that I'm not sure if they are using the normal USB connections or not, I don't want to do more damage to the unit.
I have noticed the the middle pins are +5V and -5V.
I have found the harness, but they charge only for the part not including the shipping almost $17.
I have everything that I need to make the harness on my own, just need the right info.
I'm thinking, if I have the harness in the unit and one more time I could boot it normally, I could do a firmware update and maybe the unit would work as it should.
There were a bunch of complaints about these units rebooting, clearing everything from the stored memory.
It looks like an EEPROM problem to me. I don't know anything about these components.
Any help would be appreciated.

[tibimakai]

Re: Kenwood DNX6990HD service manual needed

How could I measure these pins and be able to make my own schematic of this USB connector?

[tibimakai]

Re: Kenwood DNX6990HD service manual needed

Anybody has any experience, or has worked on these kind of units ?
There is another forum where they repair these units?
In every forum, people have issues with these units, the only option is to send it to Kenwood for repair.
I have picked up another unit, the DNX5120 from Ebay, which I haven't got yet.
This unit it's working fine except the Garmin part, which shows a black screen.
The only option is to send it to Kenwood and they repair it for something around $600. It seems crazy expensive. Basically they replace the nav. board.
What could go wrong?
I will get the unit and take it apart, to check out this nav board.
In only one forum I have found an issue, somebody got an answer from Kenwood. They said, that the cause it was a fuse. It could be a surface mount fuse? I will see when I will open it up.
This 6990HD unit that I'm working on now, it seems that it's working much better after a reset(Mute+Tel, then Reset).
It still has probably the first firmware on it that came from the factory and maybe that is the cause of the problem.
I'm hoping that, after upgrading the unit with the latest firmware, it will take care of this rebooting issue.
I have just found a missing wire from the wire harness, the emergency brake wire. Need to find the pinout, to see where it should be in the connector. There are a couple of empty locations.

[tibimakai]

Re: Kenwood DNX6990HD service manual needed

Nobody is working or has experience with these or similar units?
There is another nice one on Ebay which doesn't power up.
I can't find the service manual for it and I don't know if I should buy it or not.
Any suggestions? (Kenwood DNX570HD)

[tibimakai]

Re: Kenwood DNX6990HD service manual needed

Found the offending device, which is the DVD drive.
If I remove it, the unit works. If I install it, it turns the unit off and then on in a loop mode.
It seems that it enters in a protection mode.
It may be a short somewhere?
The question is that the drive is the issue or some controlling components on the main board?
A new drive it's pretty expensive($158+tax+shipping).
I don't have the service manual, but I could purchase it for around $20+tax+shipping from pacparts (B53-0939-00).
Managed to update the unit's firmware, including the Bluetooth. Got the USB cable from the same place.
Any input?

[tibimakai]

Re: Kenwood DNX6990HD service manual needed

I guess, I won't get much help from this forum.
Anybody knows where is a forum, where they repair these or similar units?

[tibimakai]

Re: Kenwood DNX6990HD service manual needed

I think that the DVD drive may have jumped some teeth inside and it's not synchronized anymore and it's sending some error signal to the rest of the unit.
I have managed to readjust some of the gears/arm/springs in there, but I still have issues realigning the door gears.
At this point, it won't turn off the unit. This proves that it's a misalignment issue causing the reboot. I just have to figure out the door gears in which way they should go together and I may be able to repair it.
I have picked up another Kenwood unit, the latest one DNX570HD.
This one has a no boot issue. First time, when I have powered it up, it turned on for like 20 seconds, the no more.
It has a LV5680N IC for power. I have to take some measurements from this IC. There is a shotky diode and a Elna(same brand as in the Harman Kardon receiver) 3300uF/16V capacitor. I'm wondering about this 16V capacitor, is not to small?
I will have to measure the shotky diode out of circuit, becuase it shows weird in the circuit.

[tibimakai]

Re: Kenwood DNX6990HD service manual needed

I can't find a service manual for this unit, but I have found another stereo's schematic, which uses the same power IC and amp IC.
If I wait for a (long) while, then it will turn one once for like 10-20 seconds nd then turns off.
What could that be?

[tibimakai]

Re: Kenwood DNX6990HD service manual needed

I managed to find a SM(I had to buy it for $28 shipped!!).
Anybody on this forum could help me with this DNX570HD unit?
Any ideas would be appreciated, a lot.
The power IC is a LV5680NPVC. After that first start up it shuts down and then if I measure the pins they are all 0V except the Vcc.
It enters in protection mode?
How should I go about checking this unit? SM doesn't help much.
Should I cut all the output traces at the PS IC, to make sure that it stays on without load?
Or should I just go ahead and replace this IC?

[tibimakai]

Re: Kenwood DNX6990HD service manual needed/DNX570HD

I took a picture with the Electrical board, where the power supply IC, amp IC, tuner board, etc. are located.
Here is the schematic of this board.
An opinion, please.
What could be when the unit powers up and then turns off. I have measured all the output voltages at the power IC and they are pretty much 0V.
If it turns on initially, the power supply IC could be still bad? After the initial start up, I can't make it to turn on again for a long time.

[tibimakai]

Re: Kenwood DNX6990HD service manual needed

I have measured one more time all the pins of the power supply IC and I have found another voltage. At pin #12 there is 4.94V (BU5V).
What else I have noticed, when the unit booted up the amp IC it was getting pretty warm. An amp IC should get warm without a source signal and without heat sink?
After that, I have cut the + trace going to the amp IC, hoping that will boot up, but it didn't happen?
Not sure what to do next. Should I replace the power IC to see if it makes a difference? Should I completely remove the amp IC, just to make sure that it's not causing any short?
I have checked, all the pins(both ICs) with an ohm meter and did not find any short.
ILUM F had a 650 Ohm value.
Service manual exceeds the forum's limit.

[tibimakai]

Re: Kenwood DNX6990HD service manual needed

Made a "diagram" for easier troubleshooting.
These are the voltages that should be there.

[tibimakai]

Re: Kenwood DNX6990HD service manual needed

Nobody can answer to that question, if an electronic device has an IC amp, without signal should heat up?

[tom66]

Re: Kenwood DNX6990HD service manual needed

Depends on the type of amplifier.
Class D = no not normally
Class AB = yes due to Iq. Feel your HK amp when it is not playing audio, it gets warm right? Same idea.

Class D = small amplifier chip no heatsink typically, class A is efficient around 95%.
Class AB = big amplifier with heatsink typically, class AB is inefficient around 35%.

[tibimakai]

Re: Kenwood DNX6990HD service manual needed

I guess it's normal then since it looks like it's a AB(maybe KB) amp IC.
I have removed it from the PCB and did not boot up, so it looks like the cause it's not the amp IC.
There is a daughter board also which gets warm. It has like a CPU on it, a micro SD card, two memory chips on it and other ICs. I believe it's called I/O board.

Back to the DNX6990HD unit.
I was reading the 570HD service manual and it seems that the DVD drive is not just as simple operation of swapping parts.
There is a factory CD and DVD that has to be used to record the limits/loading/ejecting of the mechanism and that data it's stored in a memory.
I'm trying to find out, for how much it would it would be done this calibration by a Kenwood service center.
At least, this unit can be used except the DVD drive. Normally, I don't even care about CD/DVDs.

[tom66]

Re: Kenwood DNX6990HD service manual needed

What is the part # on the amp chip?

[tibimakai]

Re: Kenwood DNX6990HD service manual needed

TB2931HD. I can't find anything about it. It's a Toshiba IC. pacparts sells Kenwood parts and they seem to be able to get it for ~$11+shipping.
This IC, it seems that it even has diagnostic features also.
Since I have removed this IC it reboots and then shuts off and then a bit later tries to boot up again. Then nothing.
It seems, that it affected the unit this removal. Doesn't act the same way as when it was installed.
I'm wondering if this daughter board is not the Windows CE 6.0 motherboard.
It has a CPU, flash drive, memories, etc.
I could send you the SM if you want. The size of the SM is 10.5 MB, so I'm not able to load it up here.

[tom66]

Re: Kenwood DNX6990HD service manual needed

Sometimes these ICs have communications interfaces for volume control and error detect, "no reply" could be considered error too, so removing it isn't a guaranteed way of ruling it out. Do you have schematic for that area of circuit?

[tibimakai]

Re: Kenwood DNX6990HD service manual needed

I have posted it above.
I have made some pictures too.
AMP IC is removed, I have just placed it there to see where it is.
First two are with the daughter board and the other two are with the "electrical board". (Power supply, Amp, Tuner)
Below the daughter board is the video board.
Heat sink is removed from the daughter board.

[tibimakai]

Re: Kenwood DNX6990HD service manual needed

You may be right, since these are pretty advance chips with there own diagnostics features.
It seems that if I remove the wide ribbon cable from the daughter board, nothing happens. I'm thinking, that this would be the computer which controls the whole unit.