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LED Replacement Board for Gear Indicator in OEM Cluster Sat Mar 10, 2018 12:16 am
robmack
Life time member
I'm finishing up working on a new electronic board and posting my progress here.
The age of our bikes means that certain electronic components, like the LCD displays in the instrument cluster, are reaching their end of life. The gear indicator is one of those components that slowly dies by having the liquid crystal fluid leak between the glass. The LCD used by BMW is special and not available from any electronic parts supplier in the world. But this is where my board comes in. The board I've designed is a drop-in replacement for the LCD gear display. It will fit on the GPI board inside the cluster and will replace a failed LCD display.
Below are pictures of my working prototype.
The board is held in with 2-56 screws in the original holes. The board shows as being a little oversize but I'll correct that in the next batch of printed circuit cards. The displays I chose are Red in colour but I can choose other colours as well. It is necessary to make one small modification to the GPI board to get this to work. The modification consists of cutting through one of the PCB traces on the board and soldering a small jumper wire across two pins on an IC. The modifications are not difficult. You can see the modification in the photo above, right at the top of the GPI card.
Others have added a LED display to the OEM GPI board but needed to heavily modify the board in the process. Not here. There are small pins that contact the original pads on the GPI board, as you can see in the photo above.
I have one last task in this project and that is to design and 3D print a part to accept the two mounting screws. Once I have that complete, I'll start to offer this for sale.
The modification is to add a small jumper as illustrated in the photo below. Once done, the GPI board will indicate gears 1 through 6 and neutral.
The age of our bikes means that certain electronic components, like the LCD displays in the instrument cluster, are reaching their end of life. The gear indicator is one of those components that slowly dies by having the liquid crystal fluid leak between the glass. The LCD used by BMW is special and not available from any electronic parts supplier in the world. But this is where my board comes in. The board I've designed is a drop-in replacement for the LCD gear display. It will fit on the GPI board inside the cluster and will replace a failed LCD display.
Below are pictures of my working prototype.
The board is held in with 2-56 screws in the original holes. The board shows as being a little oversize but I'll correct that in the next batch of printed circuit cards. The displays I chose are Red in colour but I can choose other colours as well. It is necessary to make one small modification to the GPI board to get this to work. The modification consists of cutting through one of the PCB traces on the board and soldering a small jumper wire across two pins on an IC. The modifications are not difficult. You can see the modification in the photo above, right at the top of the GPI card.
Others have added a LED display to the OEM GPI board but needed to heavily modify the board in the process. Not here. There are small pins that contact the original pads on the GPI board, as you can see in the photo above.
I have one last task in this project and that is to design and 3D print a part to accept the two mounting screws. Once I have that complete, I'll start to offer this for sale.
6th Gear Modification
Slightly related to this, it is possible to modify the BMW GPI board to indicate 6th gear. I helped a guy with this modification as he was installing a K100 cluster on a three-wheeled vehicle.The modification is to add a small jumper as illustrated in the photo below. Once done, the GPI board will indicate gears 1 through 6 and neutral.
Last edited by robmack on Sat Mar 10, 2018 3:31 am; edited 1 time in total
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Robert
1987 K75 @k75retro.blogspot.ca
