HP 3457A Service Manual page 163

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3457A Replaceable Parts
6-26
Table 6-5. List of Part Changes (cont'd)
An Capacitors A2C101, A2C201 and A2C202, part no. 0160-4479 (220pf) have been replaced
with part no. 0160-6842 (220pf) for compatibilty with the HP 3457 production process. Both
parts are electrically identical. The new part will be found on A2 Assemblies which have an
ERC of 2712 or greater.
A, Capacitor A2C5I1, part no. 0160-4438 (470pf) has been replaced by part no. 0160-6839
(470pf) for compatibility with the HP 3457 production process. This part will be found on
A2 Assemblies which have an ERC of 2712 or greater.
A, Crystal ALY500. part no. 0410-1553 (8.000 MHz), has been replaced, in all applications, with
part no. 0410-1864 (7.980 MHz) to reduce RFI caused by harmonics of the inguard oscillator
and the outguard oscillator adding.
A, Relays A2K101 and A2K 103, part number 0490-1337, have been replaced with part number
0490-1606 in all applications to ensure contact resistance stability, The new parts will be
found on A2 Assemblies which have an ERC of 2710 or greater
Ag Capacitors A2C204 and A2C516, part no. 0160-4461 (150pf), have been replaced with part
no. 0160-6840, in all applications, for compatibility with the HP 3457 production process.
The new parts will be found on A2 Assemblies which have an ERC of 2721 or greater.
4, Capacitors A2C814 (.1uF), A2C815 (4.7uF), resistor A2R808 (2k), and A2U808 have been
added to the Al Assembly to eliminate the possibi of two channels being closed when the
power switch is switched to OFF. The Al Printed Circuit Board becomes Revision B.
A, Capacitors A2C859 (.luF), A2C860 (4.7uF), resistor A2R865 (2k), and A2U856 have been
added to the Al Assembly to eliminate the possibility of two channels being closed when the
power switch is switched to OFF, The Al Printed Circuit Board becomes Revision B.
A. Battery AIL BT601 (2.9V), part no. 1420-0278, and resistors A11R644, part no. 0698-4482, and
ALLRO45, part no. 0757-0445, are replaced by Battery AIIBT601 (34V), part no. 1420-0298
and resistors AI] R644, part no. 0757-0445, and AILRO45, part no. 0698-3359, for compatibility
with the HP 3457 production process. The new battery is not compatible with the old resistor
network. The new parts are on assembly All, ERC no. 2850 and greater.
4 Keyceap and pushrod found on Al, AIMP! and AIMP2, are not supplied when replacing an
4
Al assembly with an All assembly. Retain both keyeap and pushrod when exchanging an Al
for an All assembly.