[MAME]

Head On
-------
Irem, 1979? / 1980?

PCB Layout
----------

    M-15L
   |---------------------------------------------------------------------------------|
   |                                                                                 |
   | DSW(8)  74175   74175   7400  74LS08   74121   M53214     |-------|      E1.9A  |
   |                                                           | 6502  |             |
   |          7432   74175   7404    7427    7442  74LS241     |-------|             |
   |                                                                          E2.9B  |
   |                                                                                 |
   |        74LS74    7432  74161   74161    7442  74LS241  74LS367  74LS367         |
 |-|                                                                          E3.9C  |
 |          M53214 74LS367   7442    7486    8216     2114  74LS157  74LS367         |
 |                                                                                   |
 |4         M53214 74LS367  74161    7486    8216     2114  74LS157     2111  E4.9D  |
 |4                                                                                  |
 |W         M53214 74LS367  74161    7486    8216     2114  74LS157     2111         |
 |A                                                                           E5.9F  |
 |Y         M53214 74LS367  74161    7486    8216    74166     2114  74LS157         |
 |                         11.73MHz                                                  |
 |            7400    7432  7404    74161    8216    74166     2114  74LS157  E6.9G  |
 |-|                                                                                 |
   |   VR3 VR2 VR1    7432  7404     7400  *74173     7400  74LS139  74LS157         |
   |                                       *74S04                                    |
   |                                                                                 |
   |---------------------------------------------------------------------------------|
Notes:
      All IC's are listed
      All ROMs type 2708 (1K x8)

      6502 clock: 1.173MHz
               *: These 2 IC's piggybacked. 74S04 on top
         VR1/2/3: 5K potentiometers
            2114: 1K x4 SRAM
            2111: 256bytes x4 SRAM
            8216: 256bytes x1 SRAM

Sound PCB
---------

M-15S
|---------------------------|
|                           |
|  NE555  NE555             |
|                           |
|  NE555  NE555             |
|               LM3900   VR1|
|                           |
|  c1815x9               VR2|
|                           |
|               LM3900   VR3|
|                           |
|                        VR4|
|                           |
|                        VR5|
|    TA7222                 |
|---------------------------|
Notes:
      PCB contains lots of resistors, capacitors, transistors etc.

      VR1/2/3/4/5: Potentiometers for volume of each sound
            C1815: Transistor (x9)
           TA7222: Power Amp

-

[Jul/19/2005]

Head On (bootleg)  
BBF = sidam?

CPU
1x Zilog Z80CPU
1x oscillator (no markings)  

ROMs
6x F2708 (1-6)
1x IC2708 (0) - broken unreadable
2x PROMs SN74S288N  

Note   
Funzionamento Non testata  
In vendita No  

Dumped 19/07/2005 

-