Hour counter on tachometer

[lourao]

Hi all,
As I found the answer on this forum about problems encountered by lots of Bav owners with their engine hour counters, I took out the tacho on my B32, dismantled the tacho and hour counter and disconnected the tiny flat cable connector behind it.
I reconnected it again and mounted it all back in place. And a miracle happened as it works fine again.
Thanks folks for taking your time giving hints to others.
Lourao

[Nigel]

If anyone decides to do the counter replacement (see Downloads page) please don't throw away the old LCD, I need one to do some tests.

[aquapore]

Hi All - does anyone know where the data (hours) is stored and when the LCD display is replaced will it read zero of the accumulated hours.

Cheers

RW

[Nigel]

Hi All - does anyone know where the data (hours) is stored and when the LCD display is replaced will it read zero of the accumulated hours.

If you replace it with a standalone unit, then yes it will be zero.

As to where it is stored ...

Like many people I had to replace my VDO tachometer hour counter, but this makes changing the division ratio almost impossible so I've bought a replacement. I've been delving a bit into the electronics, two main reasons:
[1] To read the hour value on the original
[2] To set the hour value on the replacement unit without running it for 1000+ hours

I have discovered that the PCB has a Philips EEPROM PCF8582C, which is where they store the hour data, as well as the division ratio etc.

See datasheet: www.nxp.com/documents/data_sheet/PCF8582C_2.pdf

I think it should be possible to read (and possibly write to) this IC in-situ, it has an I²C-bus interface.

There is also a 6-way FFC socket to the LCD glass, or the connector pins are easily accessible on the rear. Reading the data here would at least give me [1].

To save me reinventing the wheel, has anyone played around with the I²C bus? I was going to play with my Bus Pirate first: http://amzn.to/1eB6yxg

[Later] I swapped the EEPROM from my old unit to the replacement, the hour counter was restored to the correct value.

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