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Model 8901B
Service
Heat-Staking Tool
The front-panel pushbutton switches have small plastic pins protruding from the back. These tabs fit
through holes in the front-panel printed-circuit board (assembly A l ) and are melted down to hold the
switch in place. This process is known as heat staking. The heat-staking tool is a standard soldering
iron with a special tip attached (see Figure 8A-2). The special tip may be ordered as HP part number
5020-8160.
CORRECT
TEMPERATURE
I
Figure 8A-2. Heat-Staking
Tip
Assembly Locations
Assemblies in the Modulation Analyzer are numbered sequentially from front to back, left to right, and
top to bottom as shown in Figures 8A-3 and 8A-3a. However, to facilitate the direct use of assemblies
from other
HP 8901 or 8902 series instruments, the sequence in the Audio Section of the instrument
is interrupted after A6. Assemblies A50 to A55 replace assemblies A7 to A9. Assemblies A13 and A14
have color-coded board extractors. (For example, assembly A13 has a brown left extractor and orange
right extractor. Thus, the color code of A13 is 13.) Assembly A1 is
part
of the front-panel assembly of
the instrument. Instruments with serial prefixes 2642A and above have slots for assemblies A71 and
A72 sandwiched between A l l and A13. Switch S4 is behind A14. Assemblies A71 and A72 and switch
S2 enable the
HP
8901B to be fitted with Option Series 030 Selective Power Measurements.
8A-4
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