I'm trying to repair a tachometer with a LCD hour meter. It's a VDO rebranded as Volvo Penta from 2004 and they all have a problem with the LCD display, which can be solved by changing the front panel with the display, but then you need to buy a new tachometer to get one. The display is connected with a 6 pin ribbon cable. There are no markings on the display. Are there any standard protocols and pin configurations for these kind of displays? Any chanche of just putting some other display in place.
Here are some photos of the unit and an instruction how to put a new hour meter in place of the old display. I would like to replace just the display.
http://verl900.files.wordpress.com/2013/01/volvo-penta-tachometer-lcd.pdfThe display can show 6 digits or alfabets (as 7 segment) and a desimal point.
On the main PCB there is a PCF8582C-2 I2C EEPROM and a 44 pin chip from NXP with a2c34128/wwg, cc6905 and tpg0437a, but I couldn't find what it is. Must be a microcontroller. The LCD ribbon is connected to the same I2C as the EEPROM, thus the LCD must be I2C.
The pinout of the ribbon is:
1. I2C SDA
2. I2C SCL
3. 5V VCC
4. GND
5. GND
6. ??, it has a 180k pulldown resistor to GND and doesn't seem to be connected to anything else.