TM 11-6625-2781-14&P-2
H23-8553B OPERATING AND SERVICE MANUAL SUPPLEMENT
GENERAL DESCRIPTION
b. Change A6C26 and A6C27 to C: fxd mylar, 0.1
F, 5%, 200 VDCW, HP Par, No. 0170-0019.
The H23-8553B is a modified version of the 8553B
Spectrum Analyzer RF Section.
The modification
c. Delete A8C20.
consists of an extra connector on the rear panel wired to
allow existing circuitry to be remotely controlled. The
d. Change A8C21 to C: fxd, elect, 0.15 F 10%, 35
H23-8553B is intended for use in an 85803A as part of
VDCW, HP Part No. 0180-2127.
the 8580A Automatic Spectrum Analyzer.
The H23- modification has been designed for use in the
SCHEMATIC DIAGRAMS
8580A under computer control. With the exception of
the Input Attenuator switch, the front panel controls
This supplement contains replacement schematic
operate as shown in the 8553B Operating and Service
diagrams for Service Sheets 2, 3, 6, 7, and 8 in the
Manual when the system MANUAL mode is selected.
8553B Operating and Service Manual.
These
The Input Attenuator is not switchable in the MANUAL
replacement schematic diagrams show the changes
mode. In the system AUTO mode, all front panel
made for the H23- modification.
controls and indicators are disabled and their functions
are controlled remotely by the computer.
MAINTENANCE
CIRCUIT DESCRIPTION
The Performance Tests and Adjustments sections of the
8553B Operating and Service Manual also apply to the
The H23- modification allows remote operation of the
H23- modification.
However, the HP 11592-60015
various functions in the 8553B. Figure 1 shows the
Extender Cable Assembly called out in the 8553B
connections to the added connector P7 and a short
manual should NOT be used. For this purpose the
description of each connection.
85813-60013 and 85813-60014 Extender Cables,
provided as part of the 85813P Service Kit should be
REPLACEABLE PARTS
used. These cables are compatible with either the
85803A/85802A or 140-series oscilloscope mainframe,
The H23- modification requires some changes to the
when testing and repair are done in the field. When
Parts List (Tables 6-3 and 6-4) in the 8553B Operating
used with the 140-series mainframe, it will be necessary
and Service Manual. The changes are as follows:
to provide +20 Vdc from an external source. If used with
the 85803A, the external power supply is not necessary.
a. Add A3CR1, Diode: Silicon, HP Part No. 1901-
0025.
E-2
