Control panel malfunction. Help please.

[The_Missile]

Dear SAAB users.

My name is Andrew. I'm from Poland.
I got to this forum with a hope that my problem will be finally resolved.

My car is 1996 Saab 900SE 2.0Turbo which I love for a performance and reliability.
But recently one problem keeps getting me mad.
A car control panel malfunction occures randomly, sometimes once a day or a week and sometimes 10 times in one hour. As far as I can say its something about a power loss.
This is a link for a video with malfunction recorded on.

http://www.youtube.com/watch?v=IfTF_EnEMFM

I have a control panel removed now.
I'm a vehicle engineer with my own workshop so I should manage to repair it all by myself. All I need is some instructions where should I look for a soldering faults inside a panel. A panel is quite complicated peace of equipment so its good to have some scheme before starting any repairs.

I'm looking forvard for any help and hints on this thread.
If You need to send me any email, this is my adress: ANDREWAQ@OP.PL

Thank You All
I'm sorry for my poor english.

Best Regards

Andrew The_Missile.

[bollman]

Hi, and welcome to STCS!

Your problem is quite common. Once you take the panel apart you'll see that it's not as complicated as one might expect. There's 2 boards. One which is easilly removed (the back side) and then another one which is more difficult to remove and you won't need to anyways.
My guess is that your problem is in the big connector since it seems the entire cluster restarts. I would inspect all the soldering on the connector.
Another common problem is that the different meters behave erraticly. That is due to bad soldering for the meters. Once you remove the back side you can easilly tell which are the ones for the meters as they are bigger.

Good luck repairing, and remember, it's not that difficult to get a working, used one from Sweden most scrappers have a few laying around which you probably can get cheap.

[The_Missile]

Hello and thank You for Your reply.

Sure I can replace a whole unit with another one but that is not the point.
I really want to repair the one I already have.
Just to be sure, is that the connector we're talking about?


I've just double checked a solderings on a big connector that You mentioned.
It looks just fine, no visible cracks on them at all.
click to zoom


I understand that it cant be clearly seen on a picture but believe me all solderings on this one looks just perfect. Also I had checked a cable instalation by using another control panel that I have in a temporary use from another Saab 900 so I'm really sure that the cable instalation works fine.

Any more sugestions?

Greets.

The_Missile

[zimm]

intermittent faults are a pain.

try touching up the soldering joints even if they look good.

i would go through the entire pcb. dosent hurt anything and makes sure that soldering is not the problem.

the next step after that is checking all the components, diodes, caps and other semicunductor and passive components.

Good luck!