1990 digital dash odometer not working

[Gibbzzz]

I have a 1990 Cutlass Supreme with a digital dash, the odometer flickers numbers or says error. Is there a simple way to fix this?

[53bruce]

I just repaired a 1991 dash that would flash and go dead, show 1/2 of the digits I used a small soldering iron and resoldered every conection. The main board doesnt appear to like flexing at all. once it was resoldered, i carefull refastened the connecter to the plastic frame then reinserted it into the car dash. It is also easier to disconnect the dash wiring if you remove the radio first.
I tried only repairing the solder joints that looked suspect, but It seemed like it was remain intermittant. So I gave up and resolder all of the joints then its appears to have been repaired.
counting thetime to take it out, resolder it, and reinstall it, about 3 hours. it helps if you have a good magnifying glass to inspect the joints as you solder to ensure you dont create more issues than you started with.
This isnt the 1st time that I have had an issue with the GM solder joints, I also have repaired the infamous "intermittant wiper moter " by resoldering the wiper motor circuit board.

[Slade901]

Here's my journey when I fixed my Digital Cluster and the main suspect was the IC (Integrated Circuit) board.

http://www.geocities.com/southbeach/...nt_cluster.htm

[53bruce]

Slade,
Just want to thank you for that excellent write up, its what inspired me to go down the path of resoldering components on the PC board. I also took some slightly different troubleshooting paths, I took the boards out of the plastic holders and carefully installed them into the vehicle wiring, where I could poke prod and twist it. I found that If I flexed the board just right, it would all come back to life. So that really implied that a poor connection was the cause of the issue.
Where I work we have seen simular issues in our QC checks of PC boards in general. we use a high power microscope to look at the solder joints and often we find that a cold solder/poor solder can cause a lot of failures. I checked out the solder connections on my board and the majority were suspect, so many that it wasnt worth just soldering a few. Ideally, you should use a solder station and a microscope for this type of repair, but if you are desparate, a 15 watt pencil , cheep solder sucker and a big magnifying glass will do.
At any rate, I resoldered them all, then before the board could be allowed to flex and potentially damage the repair, I fastened the PC board back into the frame. It has worked well since that time.
My guess is that the holes in the PC board for the component leads are problably just a little bit too big. Then since the lead cant make a good mechanical connection, the solder picks up the load. repeated stress then worries the solder to the point that it fractures and the board fails. about the only way to really correct this would be epoxy the parts down.
As I have mentioned earlier, I have seen this same weakness on the Chevy Blazer windshield wiper motor control board. And I used the same general method to cure that issue too.
Once again, Thanks!