Zeiss humphrey HFA II-i series Field Service Manual page 506

Instrument: Humphrey Field Analyzer II-i
Subject: Power Supply P/N F57974
Status: Mandatory – Check Next Visit
Problem
The HFA II-i Power Supply, P/N F57974, has a potential to fail under moderate load conditions.
Cause
The Power Supply diodes, rated at 100 Volts, can experience voltages exceeding 100 Volts. If the
voltage exceeds the 100 Volt rating, the diode(s) may fail, causing the Power Supply to fail as well.
Solution
The Power Supply manufacturer has determined that replacement of the 100 Volt rated diodes, with a
150 Volt rated diodes, prevents diode and Power Supply failure. The manufacturer has incorporated the
150 Volt diodes on all new and reworked Power Supplies.
Power Supply Replacement
To determine if the HFA II-i instrument has an affected power supply:
1) Verify that the instrument serial number is in the range shown in Table 1. If the serial number is
NOT shown in Table 1, the instrument is not affected. No action is required.
2) If the instrument serial number is in Table 1, inspect the label on the power supply. If the label is
as shown in Figure 1, the power supply has the 100 Volt diodes. In this case, replace the power
supply.
3) Order part number F57974.
4) If the label is as shown in Figure 2, the power supply has been reworked with the 150 Volt diodes.
No action is required.
Table 1: The Affected Serial Number (S/N) Range of HFA II-i Instruments
Note - Credit will only be given for Power Supplies that meet the above stated criteria, which have been
returned to CZMI for inspection by September 30, 2008.
ÚÚÚ
Model
720i
740i
745i
750i
PROPRIETARY and CONFIDENTIAL
SERVICE
BULLETIN
Serial Number Range
8006 - 8177
16212 - 16550
6131 - 6259
11586 - 11842
ÚÚÚ
No.: FA2i-044A
Date: 12 Feb 08
Pages: 2