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DACS App Note

Replacing EEPROMs in RIUs (#25)


The purpose of this application note is to provide the user with the details of how to replace RIU EEPROMs. Do not undertake this procedure unless you have been authorized to do so by ASTi.

NOTE: The user assumes all risk for performing this procedure. If any damage to the RIU is incurred while performing this process, any necessary repairs will not be covered by ASTi's warranty policy. To quote an old phrase, "You break it, you buy it".

Equipment Needed

  • RIU(s) needing EEPROM replacement
  • Replacement EEPROM(s)
  • Chip puller
  • ESD-safe work area


  1. Remove the RIU from service by disconnecting its power supply, TDM, audio and serial device cables (if used).
  2. Transport the RIU to the ESD-safe work area and ground yourself.
  3. Remove the RIU faceplate and bezel. The RIU has 2 faceplates, it is easiest to remove the faceplate from the end that has the TDM ring connectors, power supply connection and address switch. Remove ONLY the 2 endplate screws!
  4. Slide the black cover from the unit.
  5. Locate the EEPROM chip, U5. U5 is a 32 pin, DIP IC that is located in a socketed holder roughly in the middle of the board.
  6. Observe the orientation of pin 1 of the chip. This is denoted by the scalloped cutout on one end of the chip. It is pointing towards the RJ-11 serial connectors.
  7. Using the chip puller, carefully remove the IC from its holder. Use caution to avoid damaging the IC or its holder.
  8. Orient the replacement chip with the holder. The scalloped cutout on the replacement IC must match the silkscreen cutout on the RIU board.
  9. Once the alignment is correct, carefully insert the new EEPROM into the U5 holder. Use a great deal of caution when performing this step because it is fairly easy to bend the legs of the IC.
  10. Once the IC has been installed, perform a visual inspection of the IC and its holder, checking for bent/broken legs or legs that did not go into their respective slots on the holder.
  11. Slide the cover back onto the RIU.
  12. Replace the faceplate and bezel in the order in which they were removed.
  13. Perform the above steps as many times as necessary in order replace all of your EEPROMs.
  14. Update the part number of the RIU to reflect the new firmware version.
  15. Restore the RIU to service by reconnecting all of its cables and power supply.