36
When installing the A4 power mesh board, lower it vertically, placing its tab into the A1 board slot, align the connector and
press in place.
A5 Diode Board Removal
After removing the cover, remove the A5 Diode board by first removing the two screws (Pozidriv) that hold heatsinks to the
A1 board, then lift vertically to remove the A5 board from the connector.
When installing the A5 Diode board, lower it vertically into the mating connector on the A1 board, then install a screw
between each heatsink and Al board.
A8 GPIB Board Removal
Remove the A8 board as follows:
a. Remove the two screws (Pozidriv, M3x.5) which attach the A8 GPIB board to the rear panel. Remove the single screw
(Pozidriv, M4x.7) that secures the GPIB board to the side frame near the front corner.
b. After removing the inside cover, unplug the W5 and W6 ribbon cables at the top edge of the A8 board, the W2 3-wire
cable from connector A8J10 and the W1 ribbon cable from connector A8J9.
c. Remove the A8 board lifting it straight up.
Install the A8 board by reversing the above steps. Lower the rear side of the board into the unit first and fit the bottom tabs
into their mating slots.
A3 Front-Panel Board Removal
Remove the A3 front-panel board by first removing the entire front panel assembly. You do not need to remove the top
cover. Follow this procedure:
a. Remove the top plastic insert by prying up with a flat-blade screwdriver.
b. Remove the four front-panel assembly mounting screws (Pozidriv M4) on the top and bottom at the comers.
c. Gently pull the front-panel assembly away from the unit as far as permitted by the connecting cables.
d. Note the locations of the four power-wire connections to the power switch and then unplug the quick-connect plugs.
e. Unplug the W3 3-wire cable from connector A1J4 on the A2 control board, and unplug the W1 ribbon cable from
connector A8J9 on the A8 GPIB board.
f. Remove the A3 board from the front-panel assembly by removing the six mounting screws (P ozidriv, M4x.7)
Install the A3 Board by reversing the steps above.
A1 Main Board Removal
Removing the A1 main board requires removing the rear-panel, all boards except the A3 front-panel board, and 17 A1
board mounting screws, four standoffs, and two bus bar mounting screws. Component-access cutouts in the bottom inside
cover allow unsoldering most A1-board components for repair without removing the A1 board.
Proceed as follows
a. Remove the A2, A4, A5, and A8 boards according to the above instructions.
b. Remove the AC power cord from the cooling fan and the four AC Input Power wires.