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Identifying and Replacing a Hybrid

When you have isolated the offending SSP, you need to pull it out of the crate and replace the appropriate hybrid. First, identify the line by referring to the diagram of the FASTBUS cable segment in the Table 2 or 3 Note that this is upside down from the map shown on the Kinetics Systems map of the cable segment. Then, use the map of SSP hybrids shown on the next page to locate the candidate faulty hybrid on the SSP.

        The Location and Position-numbers of the 14 SSP Hybrids

Fastbus Cable Function Mnemonic :     SLAC #    Quick
                                                Reference
---------------------------------------------------------
AL0     AL5     AR      SS1     :       G6N3    H-A1
AL1     GK      WT      SS2     :       G6N5    H-A2
AL2     SR      DK      RD      :       G6N7    H-A3
AL3     AK      DS      MS0     :       G6N9    H-A4
AL4     AS      SS0     MS1     :       G6O1    H-A5
---------------------------------------------------------
AD3     AD7     AD11    AD15    :       E5N3    H-B1
AD2     AD6     AD10    AD14    :       E5N5    H-B2
AD1     AD5     AD9     AD13    :       E5N7    H-B3
AD0     AD4     AD8     AD12    :       E5N9    H-B4
RB (?)  NU (?)  NU (?)  NU (?)  :       E5O1    H-B5
---------------------------------------------------------
AD16    AD20    AD24    AD28    :       C4N3    H-C1
AD17    AD21    AD25    AD29    :       C4N5    H-C2
AD18    AD22    AD26    AD30    :       C4N7    H-C3
AD19    AD23    AD27    AD31    :       C4N9    H-C4
---------------------------------------------------------

                        Quick Reference Key 

        ================  TOP  ==========================
        C       H-A1    H-A2    H-A3    H-A4    H-A5    C
        R                                               A
        A       H-B1    H-B2    H-B3    H-B4    H-B5    B       (front)
        T                                               L
        E       H-C1    H-C2    H-C3    H-C4    empty   E
        =================================================

The hybrids are the tall black SIP's near the front of the SSP control board (the half of the SSP with the front panel). Replace the hybrid with a new one. Spare hybrids are found on the bottom shelf of the spares cabinet in a small gray box as of this writing. Put it in the right way, using the dot which marks pin 1; they all go in the same way. For an SSP II, one of the pins should be folded up or snipped off (this was to provide compatibility with another kind of hybrid). Just compare the new hybrid with the old to determine which one, and make sure the stub doesn't contact the socket.

Then carefully replace the SSP in the crate; you should meet very little resistance to inserting the card, yet it should push all the way to the backplane in the crate. Restore some or all of the cables for the cable segment, and check the offending line again.

  
Table 2: Top cable segment connector on front panel of SSP.

  
Table 3: Bottom cable segment connector on front panel of SSP.

Care should be taken to:

If this does not cure the problem, check to make sure that you had the right SSP and the right hybrid. If you did, call me (516 689 2991). If you didn't, try again.



next up previous
Next: SSP Diagnostic Programs Up: E-787 Technical Note Previous: Binary Search of



John Haggerty
Thu May 4 15:36:13 EDT 1995