43 lines
2.1 KiB
Plaintext
43 lines
2.1 KiB
Plaintext
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PART XII. HOW THE ESN IS REPLACED
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It takes some electronics skill to pull or unsolder the ESN. If you
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are sketchy about messing around with your phone, I suggest practicing on
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something else first, like an old calculator or something. It is also a
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good idea to use the proper tools (A very small soldering tip,chip pullers,
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It is imperative NOT to touch any of the surrounding connections, soldering
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joints, or chips. The job MUST be done right the very first time. After
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that it is not so important, because after the first time you should have the
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ESN information stored safely to disk. The only dangers remaining are
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physically damaging the chip. (Note: There are devices that wipe PROMs
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clean in the event of programming errors).
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When removing the ESN, try to follow these 5 steps:
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A. Remove the PC board containing the ESN from the entire phone unit. The
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boards are usually screwed in with Phillips heads. This will insure
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against damage to the rest of the unit.
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B. Ascertain the correct chip. Find the letters on the chip, and check it
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against the letters from the IDENTIFYING THE ESN section. Refer to the .Gif
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file included if necessary.
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C. It is a good idea to draw a sketch to help you remember which way the chip
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went in. You may laugh, but do it anyway.
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D. Carefully remove the chip. Take your time and use the proper tools.
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E. Solder in a zero insertion force (ZIF) replacement, so that replacement
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chip can be changed easily.
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After the ZIF socket has been successfully soldered in, reinsert the
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ESN and attempt to make a phone call (Be sure the NAM is programmed
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correctly). If it doesn't, check the leads on the ZIF to insure that you
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have soldered them correctly. After that, insert your ESN into your PROM
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reader and make sure it provides some sort of reading. You should use the
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search mode to look for the manufacturers serial number.
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(see MANUFACTURER'S ESN CODE LISTING) to identify the address on the PROM
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where to reprogram the ESN.
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*****************************************************************************
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