Well, here goes a piece of ASCII art, I hope.  Remember that the backplane
comes in 4 sections ABCD, each of which has 2 sides 1 and 2, and several
slots.  So the CPU board goes in slots 1A and 1B.  Looking at the backplane
from the pins, it is something like this:

    ---------------------------------
    |   D   |   C   |   B   |   A   |   this is row 1
    ---------------------------------
					continue with row 2, ...

Next step of enlargement: look at connector A.
(B is identical, just placed one unit to the left)

Each character represents a pin.  The spacing is staggered.

  U1  S1  P1  M1  K1  H1  E1  C1  A1
V1  T1  R1  N1  L1  J1  F1  D1  B1
  U2  S2  P2  M2  K2  H2  E2  C2  A2
V2  T2  R2  N2  L2  J2  F2  D2  B2

Quick sanity check:  the "1" side of the board has the components on it.

With the board held component side down, handles away from you, the
connector finger on your left is AA2.  (connector A, pin A, side 2)
It is followed by AB2, AC2, ... up to AV2. (connector A, pin V, side 2).

The next set of connectors to the right starts with BA2 and runs to BV2.
The side-1 fingers are on the other side of the board (obviously).

Notice that the alphabet is ABCDEFHJKLMNPRSTUV
No characters that could be confused with numbers.



BIRQ5	AA1	    MSpareB AL1		BDCOK	BA1	    MSpareB BL1
+5	AA2	    BIRQ4   AL2		+5	BA2	    BDAL07  BL2
BIRQ6	AB1	    GND	    AM1		BPOK	BB1	    GND	    BM1
-12	AB2	    BIAKI   AM2		-12	BB2	    BDAL08  BM2
BDAL16  AC1	    BDMR    AN1		BDAL18  BC1	    BSACK   BN1
GND	AC2	    BIAKO   AN2		GND	BC2	    BDAL09  BN2
BDAL17  AD1	    BHALT   AP1		BDAL19  BD1	    BIRQ7   BP1
+12	AD2	    BBS7    AP2		+12	BD2	    BDAL10  BP2
SSpare1 AE1	    BREF    AR1		BDAL20  BE1	    BEVNT   BR1
BDOUT	AE2	    BDMGI   AR2		BDAL02  BE2	    BDAL11  BR2
SSpare2 AF1	    +5B	    AS1		BDAL21  BF1	    +12B    BS1
BRPLY	AF2	    BDMGO   AS2		BDAL03  BF2	    BDAL12  BS2
SSpare3 AH1	    GND	    AT1		SSpare8 BH1	    GND	    BT1
BDIN	AH2	    BINIT   AT2		BDAL04  BH2	    BDAL13  BT2
GND	AJ1	    PSpare1 AU1		GND	BJ1	    ASpare2 BU1
BSYNC	AJ2	    BDAL00  AU2		BDAL05  BJ2	    BDAL14  BU2
MSpareA AK1	    +5B	    AV1		MSpareB BK1	    +5	    BV1
BWTBT	AK2	    BDAL01  AV2		BDAL06  BK2	    BDAL15  BV2
+12	AD2	    BDAL06  BK2		BDMGI	AR2	    BWTBT   AK2
+12	BD2	    BDAL07  BL2		BDMGO	AS2	    GND	    AC2
+12B	BS1	    BDAL08  BM2		BDMR	AN1	    GND	    AJ1
+5	AA2	    BDAL09  BN2		BDOUT	AE2	    GND	    AM1
+5	BA2	    BDAL10  BP2		BEVNT	BR1	    GND	    AT1
+5	BV1	    BDAL11  BR2		BHALT	AP1	    GND	    BC2
+5B	AS1	    BDAL12  BS2		BIAKI	AM2	    GND	    BJ1
+5B	AV1	    BDAL13  BT2		BIAKO	AN2	    GND	    BM1
-12	AB2	    BDAL14  BU2		BINIT	AT2	    GND	    BT1
-12	BB2	    BDAL15  BV2		BIRQ4	AL2	    MSpareA AK1
ASpare2 BU1	    BDAL16  AC1		BIRQ5	AA1	    MSpareB AL1
BBS7	AP2	    BDAL17  AD1		BIRQ6	AB1	    MSpareB BK1
BDAL00  AU2	    BDAL18  BC1		BIRQ7	BP1	    MSpareB BL1
BDAL01  AV2	    BDAL19  BD1		BPOK	BB1	    PSpare1 AU1
BDAL02  BE2	    BDAL20  BE1		BREF	AR1	    SSpare1 AE1
BDAL03  BF2	    BDAL21  BF1		BRPLY	AF2	    SSpare2 AF1
BDAL04  BH2	    BDCOK   BA1		BSACK	BN1	    SSpare3 AH1
BDAL05  BJ2	    BDIN    AH2		BSYNC	AJ2	    SSpare8 BH1
