MPG and dash cluster !!!
Thread Starter
Racer
Joined: Jul 2002
Posts: 447
Likes: 0
From: Malta Europe
MPG and dash cluster !!!
Sory for the dodgy pic but I couldn`t get one better !!!
What seems to be the problem with my MPG guage , seems one of the numbers is missing a part of it !!! How can I fix this ????
Thank you for your help :cheers:
Team Owner
Joined: Mar 2000
Posts: 83,383
Likes: 87
From: Boston, MA
Re: MPG and dash cluster !!! (marlon88)
The bad news is, you might not be able to fix it. The good news is, you might be able to fix it. This is why I say it.
The way our dashboards work is that all of the liquid crystals are ON by default. While on they block out the colored light that is filtered through a colored piece of plastic behind them. The dashboard displays the #s by turning off the indivifual LCDs to let the colored light through.
So... it looks like that particular LCD cell is on and won't turn off for whatever reason. Does the area have a "bleed through" look to it? Or are the lines still nice and sharp? If they look bled out then your LCD has failed. If they are sharp then it may just be a connection issue that removing, disassembling, cleaning, and reassembling may fix.
The insides of the dash are interesting. There are these rectangular pieces of rubber that remind me of pencil erasers that have conductive material running through tehm. These pieces are sandwiched between the LCD pane and the circuit board.
The way our dashboards work is that all of the liquid crystals are ON by default. While on they block out the colored light that is filtered through a colored piece of plastic behind them. The dashboard displays the #s by turning off the indivifual LCDs to let the colored light through.
So... it looks like that particular LCD cell is on and won't turn off for whatever reason. Does the area have a "bleed through" look to it? Or are the lines still nice and sharp? If they look bled out then your LCD has failed. If they are sharp then it may just be a connection issue that removing, disassembling, cleaning, and reassembling may fix.
The insides of the dash are interesting. There are these rectangular pieces of rubber that remind me of pencil erasers that have conductive material running through tehm. These pieces are sandwiched between the LCD pane and the circuit board.
Safety Car
Joined: May 1999
Posts: 3,651
Likes: 5
From: Atlantis
Cruise-In I Veteran
Re: MPG and dash cluster !!! (scorp508)
It looks like a bad connection in you display.
Those are "seven segment" display digits and you just have one of the segments that has lost its connection to the digit driver IC in the dash.
It's entirely possible to fix this if you're pretty good at disasembling things.
You need to be pretty good at getting them back together, also.
Take it apart and look for bad connections. Especially bad connections on the back of the PCB (Printed circuit board) A 16 power magnifying glass will help a lot looking for something like this. Check with a coin or stamp collector store to get one if you don't have one already.
A good eye loop can aid in finding this, also.
Work CAREFULLY and with PATIENCE. Don't force anything.
You'll need a LOW WATTAGE soldering pencil , preferably a temperature controlled unit to solder any questionable connections.
Good luck with it.
Those are "seven segment" display digits and you just have one of the segments that has lost its connection to the digit driver IC in the dash.
It's entirely possible to fix this if you're pretty good at disasembling things.
You need to be pretty good at getting them back together, also.
Take it apart and look for bad connections. Especially bad connections on the back of the PCB (Printed circuit board) A 16 power magnifying glass will help a lot looking for something like this. Check with a coin or stamp collector store to get one if you don't have one already.
A good eye loop can aid in finding this, also.
Work CAREFULLY and with PATIENCE. Don't force anything.
You'll need a LOW WATTAGE soldering pencil , preferably a temperature controlled unit to solder any questionable connections.
Good luck with it.
Burning Brakes
Joined: Dec 1999
Posts: 984
Likes: 154
From: Columbia MD
Re: MPG and dash cluster !!! (scorp508)
Scorp, thanks for that straight-forward explanation of how the early C4 LCD display works. I never knew that they worked by turning-off a segment to allow the light to pass through. That's a useful piece of info.
Thanks!
Thanks!
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Joined: Apr 2001
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From: Omaha, Ne GO BIG RED
Re: MPG and dash cluster !!! (LWesthaver)
I replaced just the tach LCD glass on mine, then a few months later the MPG started going out, so I got a cluster off of EBAY. Cost me < $250 and was flawless when I got it. Swapped my odometer wheels (so it kept my mileage) and haven't had a problem since. Also a good idea to replace the dash bulbs in it while you are working on it.
