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                                   BULLETIN
                FSB-101 - WORKHORSE NON-VOLATILE RAM CORRUPTION
                            DATE/REV:  01SEP96 / 0
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ABSTRACT:  Non-Volatile RAM (NVRAM) in Workhorse ADCPs fails to retain data.

INSTRUMENT/PROGRAM AFFECTED:  All Workhorse ADCPs (Monitor, Navigator, Senti-
nel) with CPU firmware version 8.12 and earlier.

DESCRIPTION:  The Non-Volatile RAM (NVRAM) in Workhorse ADCPs fails to retain 
its data.  An indication that this problem exists is a "NVRAM is Corrupt" mes-
sage when a BREAK is sent.  This message means the CR0 (load user defaults)
feature will not work.  The component we use for NVRAM can fail to retain data
stored in it.  NVRAM backs up user-command settings that were entered into
static RAM.  This is because static RAM is only valid for eight hours after
power is removed.

In most cases, NVRAM is not required for data collection.  During deployment
procedures, the INITADCP.EXE program loads the commands you selected with the
PLAN.EXE program into both static RAM and NVRAM.  The ADCP CPU uses static RAM
when the ADCP is in operation.  The NVRAM is a backup of the user commands
that only loads during the initial power-up of the ADCP.

When the ADCP loads user commands from NVRAM to static RAM during power-up and
finds that NVRAM is bad, the factory default commands stored in flash RAM are
loaded into to the static RAM.  Factory default commands may differ from user
commands; therefore, the user-desired commands may not be available for data
collection.  You must manually reload all your user-command settings into
static RAM to deploy with the system with your desired command set.

NOTE:  THE MESSAGE "NVRAM IS CORRUPT" DOES NOT DEGRADE ADCP PERFORMANCE OR
ENDANGER THE ADCP DEPLOYMENT.

SOLUTION/ACTION:  

Short Term - Always download ALL parameters for the deployment after power is
applied.  Do NOT rely on the CR0 and CK commands to load user settings.

Long Term - Contact RDI after 30SEP96 for the latest Workhorse ADCP CPU firm-
ware version (8.13).  This version of firmware will correct the problem.
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