Resolving Audi A6 C6/Q7 Odometer Backlight Issues: Intermittent Lighting & Cold-Start Failures

Hello,

I am able to pay a good price today for helping to solve this "mystery". I've had 4 cases and I can't figure it out, I'm too thin.
Odometer Audi A6 C6 or Q7 before 2010, this one with luck.
A common ailment in these meters is a broken secondary winding, then the display has no backlight and the matter is clear.
Complications for me start when the backlight is off and on. At the moment I have 2 on the table. One of them doesn't work when it's cold, but it starts working when it's warm. It would suggest a cracked February, but I have already soldered all the resistors on the board and it did not help. In another one I did before, the loudspeaker did not work with the lack of backlight.
The other one I have in front of me now has slightly different symptoms. After applying the power, the backlight turns on for 10 seconds, then goes off every time.


I am going to go further today, for MOSFET, for HC08AG, for 74HC74D, but maybe in the meantime one of you will help.


greetings

did you get it? I'm starting to fight the meter from my car (a6 c6, how cold is Fis after about 30-40 seconds it starts to appear) I'm planning to replace the transformer and see

What is the value of the fuse after the transformer? This SMD.

This is a fuse? If so, I have it burned. I thought maybe it was some kind of capacitor. You would have to compare it with a working board.

PstryPtak wrote:

I thought maybe it was some kind of capacitor

You thought right

At the current prices for meters, it makes no sense to tinker with another one - I myself replaced the trafo, mosfet and two more elements and no improvement - I did not want to look any further ...

szmiergiel wrote:

With the current prices for meters, it makes no sense to tinker with just replacing it with another one

Sure, after a short time, again exchange for another, then for another, why mess with

This guy tinkers with A6 meters https://www.facebook.com/groups/561778317833694/user/100001769464606 ask if you are on FB.

rosak wrote:

szmiergiel wrote:

With the current prices for meters, it makes no sense to tinker with just replacing it with another one

Sure, after a short time, again exchange for another, then for another, why mess with

No lift counter and the matter is settled Then I threw the pre-lift clocks but from 2008 - I think that this problem was not there anymore, but I can be wrong. FIs worked fine and until I sold the car it was functioning normally

Added after 1 [minutes]:

cuuube wrote:

This guy tinkers with A6 meters https://www.facebook.com/groups/561778317833694/user/100001769464606 ask if you are on FB.

The link will be inactive if someone is not a member of the group

szmiergiel wrote:

I don't think the problem was there anymore

The problem is just another

szmiergiel wrote:

ink will be inactive if someone is not a member of the group

Group

AUDI A6 C6 RETROFIT

user (group admin)

Andrzej Jaskulski

Trafo and Mosfet replaced and it did not help.
Heating the processor and two flashes causes the display to work.
I replaced it with a second counter. I will leave this damaged one for testing.

PstryPtak wrote:

Trafo and Mosfet replaced and it did not help

It helps on average in 2/10 of cases.