Fault Identification - Teledyne 440 System Manual

2. Release the single 12-way internal connector by pressing its two side-clips together. Remove
the end-cap.
3. Follow the same procedure to remove the other PSU end-cap.
4. Pull the end-cap forward and disconnect the single ground connection at the spade terminal.
5. Pull the end-cap carefully from the body. Save the desiccant pack.
Reassemble the PSU:
6. Check the condition of the two rubber O-rings that seal each of the end-caps. Clean or renew
them if necessary. Apply a thin smear of approved lubricant to the rings to ensure they make
an efficient seal when you reassemble the PSU. For this purpose, use the same type of lubri-
cant that you use for the sub-sea electrical connectors – see
Connectors" on page 4-3
7. Insert the end-cap that carries the circuit board first.
8. Reconnect the ground strap at the spade connector and receptacle.
9. Place the desiccant pack inside so that it fits between the card carrier and the PSU housing.
Make certain that there are no trapped wires or components and push the end-cap and card
carrier home. Ensure that there is nothing to obstruct the free rotation of the small board-
mounted fan.
10. Carefully align the end-cap to the PSU housing so that the four securing screws will engage
properly. If necessary, turn the end-cap slightly to achieve perfect alignment. Ensure that the
two holes for the grub screws align with the hardened stainless steel inserts on the end of the
PSU housing.
11. Reconnect the 12-way connector to the other end-cap. Make certain both locking clips engage
properly on the connector.
12. Align the end-cap with the PSU housing and push it home. If necessary, twist the end-cap
slightly to achieve perfect alignment of the screw holes. As you replace the end-cap, the PSU
housing may become slightly pressurised which may make the cap difficult to replace. Do not
apply excessive force.
13. Insert the four M4 × 12mm A4 stainless steel screws and use the 3mm hexagonal key to
tighten them evenly. Insert both grub-screws and tighten them lightly.

9.3 Fault Identification

The remainder of this section includes advice and a series of flow charts to help you locate a fault in
the sub-sea components of the 440 System. The SDC oscilloscope function is a powerful fault
identification tool.
Teledyne TSS has gathered considerable experience with the 440 System in
many survey operations and under a variety of conditions and has used this expe-
rience to compose the following flow charts.
DPN 402196 Issue 4.1
for these important instructions.
NOTE
© Teledyne TSS
9 – Maintenance
section 4.1.2 "Care of Sub-sea
9- 9