Service; Introduction; Service Aids; Schematic Diagram Symbols And Reference Designations - Agilent Technologies 5517B Operation And Service Manual

SECTION VIII SERVICE

8-1. INTRODUCTION

8-2. This section contains service information for the HP 5517B Laser Head. Also included are safety considerations,
theory of operation, block diagrams, schematic diagrams, component locators, and troubleshooting and repair
procedures. Other useful service information also provided in other sections of this manual include: performance
tests in Section IV, adjustments in Section V, and exploded view illustrations and parts lists in Section VI.
8-3. Theory of Operation
8-4. The theory of operation is presented at two levels:
• Block Diagram Description. These paragraphs describe the laser head's major functional blocks and
modes of operation. The description references the HP 5517B Laser Head Block Diagram,
• Board Level Theory of Operation. These paragraphs are arranged by assembly number order and
describe the circuitry at the component level. The descriptions are used with schematic diagrams for
A1, A2, and A3.
8-5. Recommended Test Equipment
Table 1-2
8-6. in Section I lists the test equipment required for service. Any equipment that satisfies the critical
specifications given in the table may be substituted for the recommended model(s).

8-7. Service Aids

8-8. This system uses both Metric and English hardware. Figure 6-1 should be used to determine the correct
hardware descriptions, part numbers, and the proper tools to employ for assembly and disassembly.

8-9. Schematic Diagram Symbols and Reference Designations

8-10. The logic symbology used on the schematic diagrams conform to American National Standard (ANSI/IEEE Std.
91-1984). This standard supersedes MIL-STD-806B.

8-11. Cleaning Printed Circuit Boards

8-12. After soldering a component to a printed-circuit (PC) board, HP recommends that you DO NOT remove the
flux from the soldered area, it has been found that after a hand soldering operation, the solder flux from RMA-P2
(Rosin, Mildly Active) solder does no harm if left in place on a PC board; the flux residue is inert and nonconductive.
However, when the flux is dissolved with a chemical, in an attempt to remove it from the board, it spreads over the
board, releasing several activators (chlorides, bromides, etc.). Now, instead of having a harmless flux residue with
the water soluble activators trapped inside, you have a potential corrosion problem. If the instrument is stored in a
humid environment, over time moisture will be absorbed which can start the corrosion process.
8-13. Figure 8-1 shows some of the symbols used on the schematic diagrams. In the center of this figure, the scheme
for printed circuit board identification is presented. Also shown at the bottom of
identify reference designators, assemblies, and subassemblies.
NOTE
A TILDE ("-") PRECEDING A SIGNAL NAME (I.E., -REF ON) INDICATES
NEGATIVE-TRUE LOGIC.
Figure 8-2.
Figure 8-1
is the method used to
65-1