@Paul
What is redesigned about the sys11 board out of interest bud
The board is not a redesign per-say but predominantly a reproduction (My bad). The Rottendog boards are a redesign in that all the drive circuits use MOSFETs and have a complete different logic for incorporating blanking.
These boards are essentially a reproduction with some modifications and (what I consider) improvements.
- The daughter boards implement successive features that Williams REMOVED during the life cycle of the board (11 -> 11A -> 11B -> 11C).
- The sound/speech section is split between digital and analog. The digital section is on the main board. The analog section is on the daughter board. The daughterboard is only needed for 11/11A/11B.
- The amplifier is on a daughter board and only needed for Sys11.
- The digit display is on a daughter board and only needed for Sys11.
- The OST (OSL daughter board) is a chargeable added feature. See here for a demo of this (This is a stand alone version demonstrated - which i will also make available - however it is a piggyback board option on Victor's Sys11 Boards) :
- The OEM board uses SRC (resistor and capacitor networks). These are no longer available. Instead this board uses resistor networks and discrete capacitors.
- The solenoid drive circuits are identical to the OEM circuit.
- The switch matrix circuits are identical to the OEM circuit.
- The lamp row drive is identical to the OEM circuit. The lamp column drive can be identical but also supports the use of MOSFETs to remove the heat dissipating 27 Ohm @ 5W resistors (This is the option i build these with). It's possible to use a TIP107 (instead of a TIP42) to reduce the current required into the base but a MOSFET is just a better solution to reduce the heat dissipation.
- There is an LED indicating 18V (lamp matrix) power.
- There are LEDs indicating the coin door (MEMPROT) state and the flipper ground relay enable state.
- The display drive circuits are identical with ONE exception. The OEM circuit uses a 74154 4:16 decoder. This IC is a DIPW-
24 and no longer available as DIPW-
24. It is however available as SOIC-
24 and using that would require a small adapter board. If you look at the RD MPU9211 you will see that it uses such an adapter. The SMT IC is mounted on the other side of the board which is why you can't see the IC. The circuit was changed to use 2x 74138 3:8 decoders cascaded together to produce the same 4:16 decoder result. The 74HCT138 (or 74LS138) is readily available as DIPN-16.
The way this works is that the base board will work as-is on a Sys11C system. System 11B needs an added piggyback DAC. System 11A also needs an added piggyback DAC (configuted diffrerently to the Sys11B one). System 11 needs the same DAC as the Sys11a, but also a Diagnostic Digit Display daughter board and a CPU Amplifier TDA2002 daughter board). The OSL piggyback is available as a chargeable add-on piggyback board.
As i've said before these will be custom built to requirements, and therefore have a leadtime of 2-3 weeks, however they are using through hole and are generally regarded in the USA as superior replacements to the RD boards. As a clue, Victor has a waiting list tens long just for these, let alone other boards. they will also be fully tested - either on my system 11 test rig or in the case of Sys11B in a real machine.