VRC5 pinout

                                  _____
                       CPU A8 -> /01 80\ ? (goes to QTA 39, maybe PRG RAM A14?)
                         VCC -- /02   79\ <> CPU D0
                     CPU A9 -> /03 (o) 78\ <> CPU D1
                   CPU A10 -> /04       77\ <> CPU D2
                  CPU A11 -> /05         76\ <> CPU D3
                 CPU A12 -> /06           75\ <> CPU D4
                CPU A13 -> /07             74\ <> CPU D5
               CPU A14 -> /08               73\ -- VCC
              CPU R/W -> /09                 72\ <> CPU D6
           CPU /RMSL -> /10                   71\ <> CPU D7
                 M2 -> /11                     70\ <- PPU /WE
               GND -- /12                       69\ <- PPU /RD
             /IRQ <- /13                         68\ ? (goes to QTA 18, maybe PRG RAM A13?)
         CIR A10 <- /14                           67\ -> PRG RAM A12
    CHR RAM A12 <- /15                             66\ -> EXT PRG ROM0 /CE
        PPU A3 -> /16                               65\ -> EXT PRG ROM1 /CE
       PPU D0 <> /17                                64/ -> EXT PRG ROM2 /CE
      PPU D1 <> /18                                63/ -- GND
     PPU D2 <> /19         VRC 5                  62/ -> INT PRG ROM /CE
    PPU D3 <> /20                                61/ -> PRG A17
   PPU D4 <> /21                                60/ -> PRG A16
  PPU D5 <> /22                                59/ -> PRG A15
    GND -- /23                                58/ -> PRG A14
PPU D6 <> /24                                57/ -> PRG A13
PPU D7 <> \25                               56/ -> QTRAM /WE
 PPU A7 -> \26                             55/ -> INT PRG RAM /CE
  PPU A8 -> \27                           54/ -> EXT PRG RAM /CE
   PPU A9 -> \28                         53/ -> CHR ROM A16
   PPU A10 -> \29                       52/ -- GND
    PPU A11 -> \30                     51/ -> CHR ROM A15
     PPU A12 -> \31                   50/ -> CHR ROM A14
      PPU A13 -> \32                 49/ -> CHR ROM A13
           VCC -- \33               48/ -> CHR ROM A12
      CIRAM /CE <- \34             47/ -> CHR ROM A11
       QTRAM +CE <- \35           46/ <> QTRAM D7
      CHR ROM /CS <- \36         45/ <> QTRAM D6
       CHR RAM /CS <- \37       44/ <> QTRAM D5
           QTRAM D0 <> \38     43/ <> QTRAM D4
            QTRAM D1 <> \39   42/ -- GND
             QTRAM D2 <> \40 41/ <> QTRAM D3
                          \   /
                           \ /

Notes:

• CPU R/W (pin 9) and CPU /RMSL (pin 10) might be reversed

Source:

• BBS