_ FCO TU78-R026, Circuit breaker CB1 trips for no valid reason




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 |  _ _ _ _ _ _ _                                                            |
 | | | | | | | | |                                  Level of       Page 1    |
 | |d|i|g|i|t|a|l|                                  Urgency        Of   4    |
 | |_|_|_|_|_|_|_|                FCO                [ R ]                   |
 |___________________________________________________________________________|
 | FIELD CHANGE ORDER                          Number: TU78-R026             |
 |___________________________________________________________________________|
 | Applicability:                                                            |
 |       Rework any Transport exhibiting problem/symptoms.                   |
 |                                                                           |
| Note: This FCO applies to any TU78 that has been upgraded to a TU78.      |
 |                                                                           |
 |    | This FCO supersedes the original release of 28 March 1985 and        |
 |   || provides the following changes: - The changing of the AC Transformer |
 |   || Tap specifications has been included. This increases the Power Pack  |
 |    | Margins. The FCO now applies to any TU78, now a TA78.                |
 |___________________________________________________________________________|
 | Problem/Symptoms:                                                         |
 |     The Circuit Breaker CB1 trips for no valid reason.                    |
 |___________________________________________________________________________|
 | Quick Check:                                                              |
 |                N/A                                                        |
 |___________________________________________________________________________|
 | Compatibility/Prerequisite FCO:                   | Est. Time to Install  |
 |                                 None              |     1.0 Hours         |
 |___________________________________________________|_______________________|
 | Special Tools or Test Equipment:                                          |
 |                                   None                                    |
 |___________________________________________________________________________|
 |                            FCO Parts Information                          |
 |___________________________________________________________________________|
 | Order by     |                     Contents                               |
 | FCO Kit #    |____________________________________________________________|
 |              | Quantity     Part Number      Description                  |
 |              |                                                            |
 | EQ-01326-01  |    1                          Parts                        |
 |              |    1         12-24448-01      Circuit Breaker              |
 | FA-04606-01  |    1                          FCO Document                 |
 |              |                                                            |
 |______________|____________________________________________________________|
 | EQ Kit Variation/System-Option Applic:                                    |
 |___________________________________________________________________________|
 |                            Approvals                                      |
 |___________________________________________________________________________|
 | CSSE Engineer          |F.S.  Product Safety     | F.S.  Logistics        |
 | Donna Reusch           |  John Freudenberg       |   Ed Duggan            |
 |________________________|_________________________|________________________|
 | Responsible CSSE Mgr   |F.S. Microfiche Libraries| Affected Population    |
 |                        |                         |   6,000                |
 |________________________|       PDP-11            |_______________________ |
 | ESD&P Micropublishing  |       LCG               | Initial Kitting        |
 |                        |       Mini              |     500                |
 |________________________|                         |_______________________ |
 | Revision               |       VAXnotes          | Hardcopy Publication   |
 |               B        |       STARS             |   2,000                |
 |________________________|                         |________________________|
 | FCO Release Date       |                         | Parts Availability     |
 |  26 October 1985       |                         |   June 1985            |
 +---------------------------------------------------------------------------+




      _ _ _ _ _ _ _               |           FCO  TU78-R0026
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     |d|i|g|i|t|a|l|              |           PAGE  2  OF  4
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   _______________________________|_________________________________________

                            REWORK PROCEDURE
                                 FOR
                              TU78-R0026

***********************************************************************
*                                DANGER                               *
*                                                                     *
*   Remove the power from the TU78 Transport Unit as indicated below: *
*   1 - Turn the Circuit Breaker CB1 to the "OFF" position.           *
*   2 - Remove the Unit A/C Power Plug from the Source Receptacle.    *
*                                                                     *
***********************************************************************

1.  Remove the two (2) screws from the front of the Breaker (CB1) and
    save them.

2.  Remove the four (4) wires from the back of the Breaker.

***********************************************************************
*                                 NOTE                                *
*                                                                     *
*         Remember the wire configuration and mark the wires.         *
*                                                                     *
***********************************************************************

3.  Remove the Breaker and discard it.

4.  Install the new Breaker with the two (2) screws saved from step 1.

5.  Reinstall the wires as they were originally configured.



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     |d|i|g|i|t|a|l|              |           PAGE  3  OF 4
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   _______________________________|_________________________________________


6.  Remove the Transformer Tap Wiring Cover (See Figure 1).




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     |d|i|g|i|t|a|l|              |           PAGE  4 OF 4
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   _______________________________|_________________________________________


7.  Reconfigure the AC wiring taps (See Figure 2).

8.  Place the decal supplied over the configuration printed on the
    cover.

9.  Replace the cover.

10. Return the A/C power plug to the Source Receptacle.

11. Turn the Circuit Breaker CB1 to the "ON" position.

12. Run the following Diagnostics:

    - EVMAA for the TU78
    - ILTAPE for the TA78

\^ TU78
\\TU78
\\TU78-R026
\\REUSCH
\\1985
\\OCT
\\FCO_DOCS