Shop OBEX P1 Docs P2 Docs Learn Events
B47AV PSOM.01 eeprom chip for ford speedometer — Parallax Forums

B47AV PSOM.01 eeprom chip for ford speedometer

metron9metron9 Posts: 1,100
edited 2009-02-21 18:07 in General Discussion
I have a friend that repairs odometers and does restoration for classic cars. He has one that needs a new eeprom because the digital output says error.

I have a few chips and he is going to bring the board over on Sunday so I can figure out the pinout on the 8 pin DIP. At least the power and ground pins.

I want to change the data to match the actual mileage of the cars odometer, he has chips that do work but the mileage is really high and the only person he knows wants three hundred to make the modification.

Does anyone know if this might be possible to do, is the chip typically a standard eeprom from one of the manufactures so one can read the data and write new data?

I have googled a bit and I see some say the clock chip has to be changed but he has many other eeproms that work fine when installed but have the wrong mileage.

I have also read some about programs that can read and modify the eeproms but why do that when i have a stamp.



▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
Think Inside the box first and if that doesn't work..
Re-arrange what's inside the box then...
Think outside the BOX!

Comments

  • PJAllenPJAllen Banned Posts: 5,065
    edited 2009-02-21 16:51
    There are lots of Universal Programmers available out there.· They can read and·write/burn PROMs, EPROMs, EEPROMs, WORMs, and so on.· Some of them·can "auto detect", if the device in question is a commercially available device it'll identify it for you.··It's not impossible that·devices such as these·may be (??) special builds like·to foil the·"tampering community".
  • davejamesdavejames Posts: 4,047
    edited 2009-02-21 18:01
    When I was working for a company that did the testing of GM's digital dashboard displays (1988 - 1990), we had need to test the oddometer chip and that required being able to change its contents. GM had gone to great pains putting in circuitry to lock out people from doing just that...but did provide a "back door" that used a custom 'unlock code' along with specialized timing of all signals involved. Attempting to change the oddometer contents without this code permamently locked the chip and caused it to output an error message to the dashboard.

    All that to say, changing the contents can be done; but without the unlock code and timing specifications, it's next to impossible and probably borders on illegal.


    Regards,

    DJ

    Post Edited (davejames) : 2/21/2009 6:06:58 PM GMT
  • PJAllenPJAllen Banned Posts: 5,065
    edited 2009-02-21 18:07
    Seems right, Dave.
Sign In or Register to comment.