Agilent Technologies AGILENT MODELS 6023A and 6028A service manual A4 Power Mesh Board Removal

A4 Power Mesh Board Removal

After removing the inside cover, remove the A4 power mesh board by lifting, using the large aluminum heatsink as a handle. Two connectors hold the A4 board at its bottom edge.

When installing the A4 power mesh board, lower it vertically into its connectors and press in place.

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, and remove the front feet by lifting the tabs and sliding toward the front of the unit.

b.Remove the four front-panel assembly mounting screws (Phillips 8-32) on the top and bottom at the corners using a Pozidriv or Phillips head screwdriver (Phillips head screwdriver may be used only with these four screws).

c.Gently pull the front-panel assembly away from the unit as far as permitted by the connecting cables.

d.Remove the ground-wire screw (Pozidriv, M4x.7) holding the green-yellow ground wire.

e.Note the locations of the four power-wire connections to the power switch and then unplug the quick-connect plugs.

f.Unplug the W3 3-wire cable from connector A1J3 on the A1 main board.

g.Remove the A3 board from the front-panel assembly by removing the five mounting screws (Pozidriv, M4x.7)

Install the A3 Board by reversing the steps above. The power wires are correctly connected to the power switch wires if they do not cross each other.

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. Component-access cutouts in the bottom inside cover allow unsoldering most A1-board components for repair without removing the A1 board.

To remove the A1 board, proceed as follows:

a.Remove the A2 and A4 boards according to the above instructions.

b.Detach the rear panel by removing the four mounting screws (Pozidriv, M4x.7) two on each side. Gently pull the rear panel away from the unit as far as permitted by the four wires connected to the A1 board.

c.Unplug the W1 ribbon cable from connector A1J1.

d.Remove the A1 board by removing the 17 mounting screws (Pozdriv, M4x.7).

e.Note locations and the unplug the two ac power wires and the two fan wires to the A1 board.

Overall Troubleshooting Procedure

Perform the troubleshooting and repair procedures which follow only if you are trained in equipment service and are aware of the danger from fire and electrical-shock hazards. Some of the procedures include removing the unit's protective covers which may expose you to potentially lethal electrical shock. Whenever possible, make test connections and perform service with the power removed.

After performing the Initial Troubleshooting Procedures, focus on developing a logical approach to locating the source of the trouble. The underlying strategy for the troubleshooting procedures here is to guide you to the faulty circuit nodes which have improper signals or voltages. It relies on you to identify the particular functional circuit to troubleshoot from symptom tables and by understanding how the unit works. It then relies on you to discover the defective component or components which cause the faulty circuit nodes. So, read the BLOCK DIAGRAM overview in Chapter 4 and read the functional circuit descriptions for the circuits that you suspect may be defective. Then return to this section for help finding the faulty circuit nodes.

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