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Idea for Universal LCD selector Interface PCB

Blackfish

Blackfish

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Universal Interface Board for the ST-V LCD Selector

While talking to @Apocalypse awhile ago I had an idea to use the current ST-V LCD Selector (made by @miisalo ) as a Universal selector for all the multi's that use dip switches for game selection. I had purchased one to use on a ST-V board I had bought, but that ended up being dead. So after having a quick look at how the selector works it look as though with a little programming, the menu could be changed to represent any multi that used dip switch style selection. However there is one major issue with the M72, C2 and at the time S16 multi's. There is no way to easily install the reset wire required to reboot the board with the newly selected game. So I got to thinking about possible solutions and came up with this.

A Universal Multi JAMMA Pass-through

As a disclaimer it was only going to be a pet project to encourage me to learn Arduino programming and PCB design. I have not discussed the re-purposing of the ST-V LCD selector with @miisalo and if he doesn't like it being used or if he wants to take over and make this himself that is fine by me.

My idea basically consists of a modified Jamma pass-through that contains the following:

  1. 2 dual channel relays to switch the 5V and 12V supplies to the PCB
  2. a transistor to drive the relay coils from the existing Reset signal from the LCD selector.(P4 or 5) This comes from one of the channels of a 4066 CMOS which cant itself drive the relay coils.
  3. a connector for the power supply to the LCD selector.(P1) This is obviously fed from the supply side of the board as we want to maintain power to the selector throughout the reboot process.
  4. a connector for the dip switches (P2) This should be enough channels to drive all the multi's dip switches. This is basically a pass-through to another connector.
  5. a connector to attached the dip switch jumpers from the multi to the pass-through board. I figure this is easier as you would just need to change the the jumper cable from the multi board rather than from the selector itself.
  6. also a LCD display for monitoring the 5v and 12v supply from the cabinet.
This is basically what I came up with as a cheap way to use the one selector for more than one multi. If possible it would be good to change the selector's code so that you can select which multi is installed and see the game selection. From my investigation so far it looks doable. I don't think I've left anything out. I just haven't had time to get my skills to the level necessary. If anyone would like to help me achieve this or advise on whether there are better ways to do it feel free.

If this is posted in the wrong part of the forum please feel free to move it mods.

Link to ST-V ST-V multicart game selector with LCD screen
 
Last edited:
Blackfish said:
There is no way to easily install the reset wire required to reboot the board with the newly selected game
Click to expand...
Why not solder a wire to the cpu /reset signal? Most jamma games can be reset this way. Some have special requirements, but generally speaking.

Can you post a photo or link to the STV selector? I'm not familiar with the device
 
brizzo said:
Why not solder a wire to the cpu /reset signal? Most jamma games can be reset this way. Some have special requirements, but generally speaking.
Can you post a photo or link to the STV selector? I'm not familiar with the device
Click to expand...
Because you don't want to hardware mod each of your PCB. And it would also look ugly.
For CPS1 we're lucky enough to have the reset signal accessible under the B-board so a probe could do the job (but location would have to be different between long and short A-boards).
 
Yeah, I was really wanting to avoid people having to do any soldering on the original boards. I think this way the risk of people accidentally damaging already hard to get boards is negated. It also means that if using it with multiple multi's there is only the one dip switch jumper cable that has to be changed between boards. This solution would probably also work with the ST-V and may remove the need for the reset connection on the motherboard.
 
Blackfish said:
Yeah, I was really wanting to avoid people having to do any soldering on the original boards.
Click to expand...
No solder solution, use a probe / grabber :P
 

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brizzo said:
No solder solution, use a probe / grabber :P
Click to expand...
Really too risky, it's easy to connect to the wrong spot and you have to now where to connect for every revision of every PCB supporting a multi.
Also on M72 source of reset signal is only accessible on the middle board, this means removing the 4 screws holding the top board then clipping to the right spot, reassemble everything and redo from scratch everytime you change of multi.

I really like the pass-through idea because it would be truly universal.
 
Resetting via relay on a JAMMA pass through would be a neat idea... you'd be just plugging in the JAMMA edge and a ribon cable to the selection header and that's it.

if you can get the PCB compact enough this could be a really elegant solution IMO.

I do feel that tapping an appropriate reset pin on the PCB is the "right way" to do it though. Soldering a wire is how this is accomplished on STV, CPS2, and F3 already. On my STV and F3 I added a simple metal post that I connect the wire to with a single pin connector, so while it does require some soldering it also means I can remove the multi without having to de-solder or cut the reset wire.

I'm curious how you'd get this to work with the C2, M72 and other EPROM based multis... the dip settings need to be available the instant the PCB is powered on else the CPU could begin running data from the wrong game. it might need to be programmed to delay the game board power until the dips are configured by the selector (or hold it in reset if you're tapping a reset point instead of using a relay) .
 
twistedsymphony said:
I'm curious how you'd get this to work with the C2, M72 and other EPROM based multis... the dip settings need to be available the instant the PCB is powered on else the CPU could begin running data from the wrong game. it might need to be programmed to delay the game board power until the dips are configured by the selector (or hold it in reset if you're tapping a reset point instead of using a relay) .
Click to expand...
Not a problem at all, you can set the dip then power the PCB a second later.
 
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