URS6 C4 - Instrument cluster problems

[sebwout]

Hi all!

I have an URS6 C4 2.2 for 1.5 years now.
The car has a ECUMaster, Garrett turbo, big IC, custom exhaust, coils, etc.
I have solved a lot of problems on the car and have driven it a lot with lots of pleasure.

There is a problem that appeared a few months ago and that I have not been able to solve yet!

The speedo and tacho started to act weirdly together.
They started indicated false reading, always both at the same time.
Example: showing 6.000tr/min and 280km/h whereas I was doing 30km/h...
Then back to normal...

It happened completely randomly and they started having moments where they did not work completely (both showing 0 tr/min and 0kmh).

Now they are always stopped and very rarely start doing stupid things...

I've tried everything;

- 10x dismantle cluster to check all the welds on the board. I've re-welded all the points I could.
- check the earth point in passenger A-post
- check the earth point in driver A-post
- check fuses

Other interesting facts;

- it's not sensor related because my odometer works and I can read my speed when I do the special reading method on the AC screen
- Although, I CAN'T read my RPM's on the AC screen
- I CAN read my RPM on my computer when connected to the ECUMaster
- The car drives normally

My guess is that I have some earth issues. because the RPM and Speedo always fail together.
Or maybe a voltage regulator on the board? I have not been able to locate it as it's not as clear as on the S2 where it's screwed on.

I would like to check the voltage, ground and signal at the back of the tacho and speedo elements, directly on the board but I don't know the pinout...

Any help appreciated on this guys!

Seb

[sebwout]

Solved! the problem was in the cluster PCB. I changed the PCB with a second hand one and everything went back to normal.
Except for the mileage shown which is not correct

Can anyone point me which EPROM contains the info so that I can swap them?

Thanks