[b3lha]

Having done that it takes just a moment or two to solder the socket in place



Then it's time to program the new chip. I am using an SST 27SF512 eeprom chip supplied by Calum and a cheap chinese Top2004 programmer from ebay. The data I am writing to it is a UK TCU image that I have modified so the economy switch will engage power mode instead. After writing the chip I read it back and verified it against the image file to ensure it had been written successfully.



Here is the modified TCU with the eeprom installed.



Then I took it out and plugged it into the car to check that it worked. And it did!!!! I used the select monitor adapter to connect to the TCU and download the part of the program that I had altered, and it matched perfectly. The very fact I was able to connect proves that the device is working. So hardware side of modifying the TCU is now possible.

However, there seems to be a bug in my software changes. The power mode is stuck on permanently. So I have to do some debugging and re-burn the eprom. But that shouldn't be too hard to do.

Phil.