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DPU & SCU Memory Failure Message


  • A memory failure message in AMT for a DPU or SCU Controller
  • When presenting a valid key card to a door reader, the LED on the SCU turns Green but the relay does not fire.  The relay can be controlled manually via the workstation in some instances.


I/NET Door Controllers 


This memory failure message is generated when the DPUs or SCUs do not have sufficient voltage supplied to the board. This can either be a bad 24 VAC Transformer or from a gel cell battery.

In most cases if there is a battery backup of the controller, the gel cell battery has had a deep discharge applied to it. The charging circuit on the controller cannot recover the battery to its proper charge value. Even if there is a good voltage value from the transformer, the charging circuit load is so great, it restricts the main board of the necessary voltage to keep the RAM alive.


  1. Remove the two wires from the controller that go to the gel cell battery.
  2. Get a replacement battery as soon as possible.
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Last update:
‎2018-09-06 12:54 PM
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