HELP ... My digital clock and boardcomputer won't work anymore ...

Hi,

Upon assembly of my dashboard everything worked fine, except for my dash lights.

So this weekend I disassembled some parts again for troubleshooting the dash lights. Seemed to be the variator in the light switch to dim the lights on the dash, after a bit of cleaning the lights worked like a charm again.

However upon reassembling I noticed that my digital clock had disappeared, it went blank … and when I switch on the contact the board computer comes on, but with some very strange characters  and after a few seconds it softly dims away.

Strange thing is, after 10 seconds or so it pops up again for a few seconds to go and stay away, until I reinitiate contact.

I thought it had to be a bad contact somewhere in a connector I must have touched when looking for my dash light problem.

So I started disassembling everything again part by part and regularly checking for the clock and computer. I even took out the whole fuse box.
Unfortunately without success, the result stays the same.

I took a little video just to make clear what I’m talking about. https://goo.gl/photos/WMxhmDgvyUfLreK78

Hope some of you guys know what this could be …Oh it's a Mk1 GTI 1.8 '83 …

I seems you have some sort of lose connection as the oil light also stops flashing, you can try and bulk out the main connector on the instruments, over time they little pins in the plug go flat so you can try a very carefully lift them up a little and on the instruments unclip the black plastic cover and care fully un hook the blue circuit board then wind a couple layers of electrical tape around the plastic tab then re assemble.
DISCONNECT the battery if pulling up the connetions on the plugs to stop anything getting shorted out.

Pictures.
Tape around plastic tab.


Plastic over back on and all back togerther.


   

I will test this for sure tomorrow.
One thing I didn't mentioned was that a previous owner fiddled with the writing on the print.
I didn't mentioned it because I drove the car for quit a few years and never had any problems with the dash. So in my understanding the problems I'm now facing can't be related to the weird things he did.

But weird it is …
He soldered a wire from connector nr 1 to connector nr 12. On this one should be a diode, but it's gone… Probably broken off when disassembling the dash.

What is weird however, I can't find what position 12 is about, but I know position 1 is for the lights in the unit… So the current being put to position 12 is 12Volt and when I would play with the regulator that current is being lowered … So this can't really be healthy for the dash I assume…

Can anybody tell me what position 12 is used for? And even better, what type of diode supposed to be in here?

That way I can buy a new one and fix it as it should be…



Thx!

Verstuurd vanaf mijn SM-G935F met Tapatalk

Hi mark1gls,
Is yours the same dash as mine? Must be my old eyes, but I can't relate your pictures to my type of dash… ?

Ok, so I cut the yellow wire to test the difference. When I now turn on the contact the oil lamp won't start blinking, so I assume that the oil warning won't work either. Furthermore it don't seem to make a lot of difference.

Unfortunately it didn't helped me on the clock/board computer problem, this stayed the same…

I also dismounted the connectors on the Mylar (both of them) to check, they actually seem to be in very good condition, everything nice and tidy, I don't think they are the problem either…

Verstuurd vanaf mijn SM-G935F met Tapatalk

Yes mines a different set of instruments in the picture as they are clocks out of a Mk1 Scirocco and that does not even have a clock or MFA, its was just some pictures for reference on wrapping the tab to make a better contact.
Sorry can't be much help on other stuff.

This is mine.

No prob, thx for trying to help!

Verstuurd vanaf mijn SM-G935F met Tapatalk

i would just try to get another set of clocks, the blue foil is fairly messed up on yours unfortunatly.

check the earth point on the side of the head though, tis the brown/white wire. there is a spade plug between the dash loom and engine loom for this one, perhaps you missed it?

rubjonny said

i would just try to get another set of clocks, the blue foil is fairly messed up on yours unfortunatly.

check the earth point on the side of the head though, tis the brown/white wire. there is a spade plug between the dash loom and engine loom for this one, perhaps you missed it?

Hi Rubjonny,

What do you mean by"side of the head"? Maybe I missed something indeed.

But as it seems, I have my earth connected, this is a single brown cable, not brown/white on my type.

I double checked it tough, unfortunately no success …

The second cable from the right.



Cheers,

Verstuurd vanaf mijn SM-G935F met Tapatalk

For a better ground, I take the Brown wire, and using a Scotch-Lok run a wire off of it


Drill a small hole between the "X's" and sand a clean spot along with a self tapping screw.



To ensure that my connector is tight and the pads are meeting the pins

Carefully remove the Shroud off the connector.


To expose the Mylar sheet covering the plastic tongue.


On the pad side of the tongue I use one piece of vinyl 3m tape.



Replace the mylar and the shroud.

Stopped a lot of flakiness in that connector and tightened it up.

Wow thank your for the pic's that made it very clear now!

I will definitely try these options once again.

 

But, as everything worked perfect until I started searching at the dashboard light issue , I have the feeling the problem lies somewhere else …

 

Idealy I had someone in the neighbourhood where I could swap my clock with for testing purposes, that would allow me to exclude the exact problem, my clock or my wiring …

 

Unfortunately no immediate MK1 lovers around here …

 

But, I will not let it stop me from finishing the car (with or without clock   )

 

Worked really hard this weekend, got the whole front assemled … And glad with the result !!






Verstuurd vanaf mijn SM-G935F met Tapatalk

on the side of the engine block there is a brown/white wire with a ring terminal, usually on a tab at the rear corner of the head or sometimes under the stud holding the side coolant flange in place

Finally had the opportunity to open up the dash again.
Unfortunately adding extra ground did not resolve the problem …

I'm a bit stuck here … No idea what to check next.
I think I've seen a German site selling mylar a time ago, will be looking for that, maybe replacing it will resolve my problem.

Anyway, other suggestions always welcome !! ;-)

Cheers

Wait.  Test the Bulbs with a meter or a 9v battery to verify that they are good.

Some times when you replace the bulbs if you don't twist the bulb in the socket just right.. it won't make contact.

Hi Briano,

To be honest I don't understand it?
There's nothing wrong with the lights of the dash they work perfectly.
It's the MFA display that's suddenly not working anymore…

Cheers

AH I misread....

Haha, no prob, end of the week for everybody I guess😉😂

look at the MFA for a Rocco, and have the



Look for the power in and ground.
Don't have other than that in my Bentley…..

did you disconnect the battery when working on the dash?, I had a similar issue and it would sometimes work if I removed fuse number 3 for a while or disconnected the battery,  and re fitted. also it seemed to work after I pulled the relay for coolant warning, think it was number 43 above the fuse box. it shouldn't effect it but it seemed to on mine, I can check my clocks later for the diode  

OMG …
One of the first things I checked where the fuses… Apparently no so thorough… :/

Thanks to your tips Sporttrucker, I noted that nr3 was blown… Replaced it, problem solved.

Haha, glad it's all that simple in the end!!

Check, doublecheck ….

Bit shameful, but many thanks to the community for helping me out!! 👍👍