Digital (A 1) Assembly Renioval - HP 3457A Service Manual

Replaceable Parts 3457A
6-21. Top Cover Removal
6-22. N o prior disassembly of the instrument is required t o remove the Top Cover. Remove the T o p Cover
as follows:
a. Remove the power cord and all external input connections from the HP 3457A.
b. Turn the unit upside down and loosen the six screws in the bottom cover. (These are captive screws.
It is not necessary to remove them completely).
c. Return the unit to an upright position and remove the top cover.
d. T o replace the top cover, reverse the order of steps a throngh c.
6-23. Display Assembly Removal
6-24. The T o p Cover must be removed prior t o removing the Display Assen~bly. Remove the Display
Assembly as follows:
a. Remove the Top Cover as described in paragraph 6-21.
b. Disconnect the plug on the back of the Display Assembly.
The pin5 o f the plug connectt7d to the display a ~ ~ e m b l y are quite fragile.
Di~connect the plug by pirlling on the rihbon cahlr rather than the plug itsrll.
c. Remove the two screws attaching the Display Assembly t o the Front Panel.
d. Remove t h e Display Assembly from the Front Panel.
e. T o replace the Display Assembly, reverse the order of steps a through d.
6-25. Digital ( A l ) Assembly Removal
6-26. I t will be necessary to remove the Top Cover prior to removing the Digital Assembly. T o remove the
Digital Assembly:
a. Remove the Top Cover as described in paragraph 6-21.
b. Remove the four screws holding the shield to the Digital ( A l ) Assembly and remove the shield.
c. Remove the power switch pushrod. Grasp the pushrod firmly near the power switch and pull it off
the power switch shaft.
d. Disconnect connectors AI-P501 (Use the white pull strap), AI-P502, A1-P701 and A 1-P702 from
the Digital Assembly.
e. Remove the two screws attaching the HPIB Connector/Heat Sink bracket t o the rear panel.