Zeiss humphrey HFA II-i series Field Service Manual page 437

SERVICE
BULLETIN
Instrument: Humphrey Field Analyzer II-i No.: FA2i-019
Subject: CPU Battery Failure Date: 20 Jun 03
Status: Informational Pages: 1
Problem
The battery in some HFA II-i computer assemblies may fail prematurely, causing the BIOS settings to be
lost. The instrument may also experience loss of Date and Time settings.
Cause
The CPU battery circuit may discharge the battery faster than normal. This may prevent the battery from
maintaining the proper charge, resulting in the above stated problems.
Solution
The CPU vendor has improved the battery circuit. We have also implemented new testing procedures on
the production line.
If the instrument loses the BIOS settings, or is losing date and time, the voltage of the battery should be
tested. If the battery voltage is less than 3.0 volts, then the CPU/Backplane enclosure should be replaced.
Note: If the battery voltage is less than 3.0 Volts, and the battery has been in the system for three or
more years, you should replace only the battery.
The serial number ranges, of instruments that may be affected, are listed below. Not all instruments within
the serial number range will be affected.
720i-5020 to 720i-5061
740i-7020 to 740i-7204
750i-8011 to 750i-8171
The CPU/Backplane enclosure should only be replaced on failure. Credit will only be given for failed
enclosures, which have been returned to CZMI for inspection. The entire CPU/Backplane Enclosure must
be returned (see service bulletin FA2i - 011).
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