1990 LCD dash non-functional, successful repair
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Intermediate
Joined: Nov 2009
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From: Salt Lake City UTAH
1990 LCD dash non-functional, successful repair
My 1990 L98 Z51 Coupe's LCD digital dash had the typical intermittent problem of going out then randomly coming back on for a year. Then it went out completely along with my VATS. Vats was solved with a 50hz signal generator. The LCD I could not figure out. I took apart the Dash and tested every circuit, the 1 inch long wire harness, everything.
What solved the problem was re soldering the entire circuit board. I used size .015 Silver Solder I purchased from Radio Shack. I also purchased Radio Shacks Soldering Pencil, The best one they sell $35. Then I re melted and added just a little more solder to make sure it went all the way to the copper on the board and did every joint on the short wire harness and the Motorola Chips first. I then went ahead and did the rest of the boards soldered joints, capacitors and resistors.
That fixed it. I don't know which one was intermittent. I now wish I had a new yellow diffuser for the LCD. Mine is a little faded and striped.
What solved the problem was re soldering the entire circuit board. I used size .015 Silver Solder I purchased from Radio Shack. I also purchased Radio Shacks Soldering Pencil, The best one they sell $35. Then I re melted and added just a little more solder to make sure it went all the way to the copper on the board and did every joint on the short wire harness and the Motorola Chips first. I then went ahead and did the rest of the boards soldered joints, capacitors and resistors.
That fixed it. I don't know which one was intermittent. I now wish I had a new yellow diffuser for the LCD. Mine is a little faded and striped.
Oil Producer
Joined: Apr 2014
Posts: 9,380
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My 1990 L98 Z51 Coupe's LCD digital dash had the typical intermittent problem of going out then randomly coming back on for a year. Then it went out completely along with my VATS. Vats was solved with a 50hz signal generator. The LCD I could not figure out. I took apart the Dash and tested every circuit, the 1 inch long wire harness, everything.
What solved the problem was re soldering the entire circuit board. I used size .015 Silver Solder I purchased from Radio Shack. I also purchased Radio Shacks Soldering Pencil, The best one they sell $35. Then I re melted and added just a little more solder to make sure it went all the way to the copper on the board and did every joint on the short wire harness and the Motorola Chips first. I then went ahead and did the rest of the boards soldered joints, capacitors and resistors.
That fixed it. I don't know which one was intermittent. I now wish I had a new yellow diffuser for the LCD. Mine is a little faded and striped.
What solved the problem was re soldering the entire circuit board. I used size .015 Silver Solder I purchased from Radio Shack. I also purchased Radio Shacks Soldering Pencil, The best one they sell $35. Then I re melted and added just a little more solder to make sure it went all the way to the copper on the board and did every joint on the short wire harness and the Motorola Chips first. I then went ahead and did the rest of the boards soldered joints, capacitors and resistors.
That fixed it. I don't know which one was intermittent. I now wish I had a new yellow diffuser for the LCD. Mine is a little faded and striped.
Excellent reporting sir! This is how it should be done to log the information for others to see and use when they have the same challenge. You should get that new diffuser. You deserve to have it working as new given your previous efforts and success.
Race Director
Joined: Apr 2002
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From: Anaheim CA
Thread Starter
Intermediate
Joined: Nov 2009
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From: Salt Lake City UTAH
Safety Car
Joined: Nov 2008
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From: Jacksonville FL
I read somewhere that a lot of times now electronics repair places will bake circuit boards at 385* which is supposed to remelt all solders and take care of any cold solder issues. I dont remember where I read this and I dont think I would be brave enough to put my $500 dash circuitry into the oven. You probly did the right thing and carefully addressed each joint. Good job!
