Reading code off of Intel 8755 die

Discussion in 'General Electronics Chat' started by pinballjail, Mar 30, 2013.

  1. pinballjail

    Thread Starter New Member

    Mar 30, 2013
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    Hello, I have a Intel 8755 that was attacked for many years by battery acid. Almost all of the legs have rotted off of the chip. It looks as if the die has been unharmed. I have read of people being able to recover code off of decapped masked rom but can it be done with eprom? If so do you know who may be able to do this. This is from an engineering prototype and would hate to have the code lost forever.

    Thanks
    Kelley
     
  2. MrChips

    Moderator

    Oct 2, 2009
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    Forget it. It would be easier to rewrite the code from scratch.
     
  3. pinballjail

    Thread Starter New Member

    Mar 30, 2013
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    I would if I could but I don't know how and I don't know who programmed it.
     
  4. absf

    Senior Member

    Dec 29, 2010
    1,492
    372
    The 8755 that I have has a glass window on it. It is also available in ROM version as 8355. I have the chip on a PROM programmer to program TTL prom 74S188 or 82S123 for answer-back chips used in the tele-printer machine.

    If you are able to solder short pieces of solid wire to the side of the chip after filing of the rusty pins, you might be able to read the memories with a circuit. The eprom inside is 2Kx8 bits just like a 2716 eprom but the address A0-A7 is multiplexed with the data lines so you would read it with a circuit using 8051 or 8085 processors

    HTH

    Allen
     
    Last edited: Mar 30, 2013
  5. pinballjail

    Thread Starter New Member

    Mar 30, 2013
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    I tried that but it didn't work on a bunch of the legs. Looks like the metal is corroded into the package.
     
  6. ErnieM

    AAC Fanatic!

    Apr 24, 2011
    7,388
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    I work with bare die. It should not matter what kind of device it is, there are general purpose headers available. And device could be opened, inserted in such a header, then wire bonded.

    "Possible" does not mean probable. It depends on the condition of the chip, both now and after it is removed from the damaged header.

    I believe there are a few companies out there that specialize in chip recovery. Expect to pay a premium for just one device.
     
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