It had become a complete annoyance to find myself driving at night with none of the instrument cluster bulbs illuminated and using a torch to keep a check on the various gauges.
After many years of constantly removing the instrument cluster to try and repair the broken tracks and preserve the instrument cluster circuit board with a soldering iron, copper tape, strands of wire and a glue gun, I drew the conclusion it wouldn’t be just me experiencing this frustration. So, utilising my passion for the 928 and all things engineering I set about designing and sourcing procurement channels for a replacement circuit board, mapped against the original circuit board.
After two years of research, development, design & testing, I arrived with something that resembled an operating prototype of the circuit board. This was a significant result, and live testing in my own 928’s commenced. 1000 miles later with a fair mix of daytime and night-time driving, the odometer and trip worked perfectly as did all the gauges. The jumpiness of the battery volt gauge and the oil pressure gauge seemed to have disappeared. The instruments seemed stable and uniform. Everything illuminated, bright and clear. But in my quest for improved longevity, reliability and resilience I developed the circuit board further; The circuit board is thicker than the original which alleviates the issue with cracking tracks, delamination and short circuits. Also, some adjustments to the tracks have been made to improve clearance issues. The new board uses the latest flexi-foil circuit board technology and materials, and the tracks are now made using Gold and not Copper for better strength, rigidity and conductivity.
The new circuit board is compatible with standard vehicle accessory store LED’s for use with the three main illumination bulbs. The dimming function works well, not that you’ll ever want to use the dimming function!
Thinking of the enthusiast’s ease for swapping out old for new circuit boards, I have also manufactured the rigid board that is riveted to the flexible circuit board along with the four pins that engage with the odometer, resulting in a complete circuit board assembly that can be swapped out as a complete plug-and-play system solution.