Hi mark
Sounds to me like the CPU is not booting up as your getting no playfield lights or DMD here some text from the
bible that may or maybe not of any be of use whatsoever
check your voltage test points?????
3r. When things don't work: Fixing a Dead or Non-Booting CPU board.
It doesn't happen often on WPC games. You have power (+5 and +12 volts) getting to the CPU board. The +5 LED (lower of the three) is on, as it should be. But the middle diagnostic LED is not flashing constantly (indicating the CPU is dead). And the blanking LED (the top one) is doing nothing (no flashes when the game is turned on). You have a dead CPU.
CPU Flash Codes, all revisions.
WPC-S and prior uses a "Dx" designation for its CPU LEDs. WPC-95 uses a "LED20x" designation.
- D19/LED201 (blanking): at power-on should be ON for about 3 seconds (1 second on WPC-95), and then turn off and stay off. When D19/LED201 is on, the blanking circuit is disabled (and will not allow any coils to be energized).
- D20/LED203 (diagnostic): After D19/LED201 turns off, D20/LED203 should stay flashing permanently while the game is turned on. This indicates the CPU is "running".
- D21/LED202 (+5vdc): this LED should ALWAYS be on. It indicates the CPU has +5 volts DC power.
D21/LED202 should *always* be on, as this indicated there is +5 volts at the CPU board. The board will never run without +5 volts!
Problem Power-On CPU D20/LED203 (diagnostic) Flash Codes.
If D20/LED203 does not flash continually, here are the flash codes diagnostics:
- D20/LED203 blinks ONE time: U6/G11 CPU game ROM bad.
- D20/LED203 blinks TWO times: U8 CMOS RAM chip bad.
- D20/LED203 blinks THREE times: U9 WPC custom chip bad (pre WPC-S), or G10 Security PIC chip bad (WPC-S and later).
- D20/LED 203 Never Blinks.
If D20/LED203 (diagnostics) never blinks (not even once) and is just off, check D19/LED201 (blanking). Is it on and staying on? If so, the first thing to suspect is a bad game ROM at U6 (or G11 on WPC-95). If the game ROM (the Read Only Memory chip that stores the game's program, which the CPU runs) is bad, the CPU will never boot (even if everything else is Ok on the CPU board.
Was this game ROM recently upgraded to a new version? Was the ROM installed correctly? (No bent pins.) Note the ROM chip has a "notch", which should be installed so it matches the "notch" on its socket. Is the ROM the correct size? (If the game's program expects a 4 meg (27040) EPROM yet it was programmed into a 2 or 8 meg EPROM, it won't work!) Is the ROM chip verified as good? (An EPROM programmer is often needed to verify the chip's checksum, or install the suspect ROM chip into another working game). EPROM chips can lose their memory and go bad (especially if there is no label over the clear quartz window on the chip). The EPROM can also be programmed incorrectly making it bad.
Some Basic Info on the WPC CPU Board.
The WPC CPU board is a pretty tight board. There is a custom ASIC chip, which controls most of the board's Input/Output functions (the ASIC is that big square custom chip). Frankly it rarely fails (actually its socket is more of a problem than the chip itself, as the socket is easily ruined by battery corrosion or somebody trying to remove the square chip without the proper tool). The next section of the board is the switch matrix, which comprises most of the components on the lower 1/3 of the CPU board (and hence generally does not stop a CPU board from booting). The only other things on a WPC CPU board are the game EPROM itself (fails rarely), and the U8 (all WPC revisions) 6264 RAM chip (which is very static sensitive, and thus can fail easily). A bad 6264 RAM chip can cause all sorts of strange CPU behavior, and due to it's static sentitive nature, it should be suspected. Also the TTL chips across the top of the CPU board (U1,U2,U3, all WPC revisions) can also fail. Beyond this, there is not much else on the WPC CPU board!
, you could not start a game, or anything.
