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LED credit display

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Fuzzguitar:

Will do my very best to get these scanned over the coming weekend. At the latest it should be Monday which is my day off, I will PM you when they're done.

This has been in the back of my mind for ages, I didn't want the cool LED display non functional under Mame if I could avoid it nor did I have the heart to rip it out.

What you are undertaking seems way out of my league currently (but don't all things when we undertake Mame as a hobby) so I will be glad to help. Other Aussies have helped me in the past and I've been looking to give something back to the community here.

Oh btw I just accquired the exact same CP you have, it will have to be very slightly modified to fit my cabinet but will allow me to fit a trackball and two spinners MUCH more easily - plus I can keep the original untouched if I ever sell the machine as a standard Jamma.

Is your CP top piece permanently nailed into the rest of it?

I was hoping to find a neat way to hinge it once I make a new top piece, really want to be able to perform maintenance if need be - have you thought of this too?

Sorry If I'm not specific enough, unfortunately my Mame cabinet is on the backburner for a while and things aren't fresh in my mind. Was just lucky I checked in here and found your post.

Scumgriever:

Yeah, the control panel on these is great. I've drawn up a template with 2 6 button controlls fpr P1&2, 2 4 button controlls for P3&4, 4 start buttons and a trackball and it doesn't look at all cramped. I'm going to leave the big square illuminated credit buttons up on the ledge bit where they were next to the credit display. I'll be happy to send that to you.

In terms on the panel being attached to the rest of it.
Mine was attached with big fat screws with alan key type heads on them, I've unscrewed those and the panel comes off beautifully. the box underneath isn't completely empty, (there are wood stabilising bits holding the panel rigid it looks like there is more than needed )  so it's pretty likely that some chopping will have to be done to fit all the controlls, specifically the trackball.

Anyway where was I... oh yeah,
I'm going to replace the alan screws (i'm making up terminology as I go, i think you get what I mean though) with shafts of metal that will allow the control pannel to slot snugly into place. The T-mouldnig holds the control panel top in place almost well wnough without the screws in at all.
 a hinge would be no trouble as far as I can see if thats what tickles your fancy. I like the idea of it being totally removable so I can replace it with a steering wheel in the future.

I'm pretty much finished with the first draft of the LED credit circuit, just a few little things to figure out, and have found a guy at work who knows this stuff much better than me who said he'd be happy to check it out to see if it will work for me. I wont get time to actually put it together untill the Uni semester finishes though (mid november). I'll give them to anyone who wants to try them though.

Druin:

To get the credit buttons to lock up when the counter is zero, use a gate on each credit button along with an address decoder tied to the counter bits.  I'm not going to be clear headed in the following, paying no attention to high/low, just the concept. 

You can use one of those P=Q  logic comparator type chips in the 74xxx series (would have to look up an exact part number).  Say the counter has 8 bits and those feed into the 7 segment drivers.  Assume the logic is set up so all bits = 0  represents a digit count value of 00.   If more bits are needed use more chips.  If there are unused bits, tie them all zero on both P and Q sides so they will always "match".

The P=Q chip has inputs for P and  inputs for Q.   You tap into the bits from the counter and feed them to the P inputs.  You tie the Q inputs all to ground because that's what you're comparing P to, to get a match of zero count value.   With this P=Q chip, the output goes high or low or whatever, maybe there's 2 outputs,  when the counter P inputs all equal the hard coded Q compare value you set.

So now you have a way to get one logic signal going to a fixed state ONLY when the counter is zero.  Use inverters wherever necessary to end up with the desired logic levels. 

Get a NAND gate or an AND gate, depending on how all the logic levels match up.  Intercept the credit switches so they each feed into one input of a gate, and the other input of each gate connects to the P=Q output trigger (through inverter if necessary).  The output of each gate goes to the keyboard coin inputs.

Another thing to keep in mind is the switches are active low with the common ground hookup, so if you are setting up logic to look for a key press, you are looking for a logic Low.   Also when you wire switches to a logic input such as the gates in this circuit, you'll need a pull up resistor at the same gate input as the switch wire to ensure the level is high rather than "disconnected/floating/ambiguous" when the switch isn't pressed. 

So there is a counter that has all its bits equal to logic low when the counter is zero.  you're hooking those bits to the P inputs of a P=Q comparator.   You're fixing the Q inputs all to logic low so that the output triggers when counter is zero.  You're taking the trigger and routing it to one input of 4 AND/NAND gates and sending a credit switch with pull up resistor to each of the other gate inputs.  The gate outputs are going to the keyboard credit inputs.  Logic is inverted as necessary so that when the button is pressed AND the counter is NOT zero, the keyboard input will be logic low.   

If the counter is non-zero value, the gates should automatically prevent the credit switch from passing through to the keyboard input.

grantspain:

www.brentelectronic.co.uk-look for quadroboss credit board in coin handling

Fuzzguitar:

Hey Scum (haha)

I managed to scan all the relevant pages from the LAI manual tonight.

There are seven pages that relate directly to you and are pretty chock full of information.

Because they are old and a little faded/yellowed I scanned them as JPEG's of 300dpi and a resolution of 3508x2480.

So all up that's 13.2MB you need to get off me, I could make them smaller of course but I really suggest you get them at this size.

Do you have a large email (gmail maybe) account I can send these to, or MSN so we can file share?

PM so we can get this happening.

Also, sorry for the delay - I have so much going on now that arcade machines have to take a backseat for a few months :(

Fuzz.

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