So at the store we recently got a Punch-Out machine and while we had been restoring it whenever we turned it on it was in free-play which is fine when we're trying to get the monitors good and testing controls and such. The problem is when we were all finished and wanted to set it to 1 coin/1 credit for the store it wouldn't work right. We are using the manual provided here (and we've double checked other sites): http://tamdb.net/P/Punch-Out!!%20%28Operation%29%20%28U%29.pdf http://www.arcade-museum.com/dipswitch-settings/9155.html No matter what setting we use we either get Free Play or 5 Coins/1 Credit. Anyone know what could be causing this? We do have access to an EPROM eraser and programmer if you think the eprom programming is the issue.
So it is on free play regardless what the dips are? If the controls work and the other dip allows you to go into test mode (and set timer speed) then it is likely that the 74LS240 octal buffer chip at 5R on the CPU board, it is less likely but the 74LS138, a 3 to 8 buffer chip at 2C could also be at fault, this is easier to test as all you need a logic probe on pin 12 and if it pulsing then it is working, if held constantly low then it may be faulty. Before replacing the chip, make sure that the resistor pack works, you should get a 1K reading between pins 2, 4, 15 and 17 and the +5V of the pack (do this whilst it is off). if you do not then replace the pack. If the pack is fine then I would cut out the 74LS240, unsolder the legs and remove the solder, solder in a high quality dip socket and use a new 74LS240 and hopefully it should work.
Did a bit more testing and if any of the dips that control the coin/credit are on it will be set to 5 coins - 1 Credit, but if they are all off it's Free Play. There is a bit of corrosion on the board near the dip switches so it's possible we may have to get a new board? I will look into your suggestions tomorrow though when I'm in the shop. Thanks very much for the useful information!
Hmm, are you sure they are all off? As free play is on on on on... I would use a multimeter to check to see if the dipswitches are working correctly and if you are getting the correct input voltages going to the chip. Clean the corrosion with a toothbrush and some rubbing alcohol and if traces are broken then solder wire across them. It does sounds like the chip is bad, but a check of the traces and components will tell you one way or another.
My mistake I had it backwards if they are all on it is on free play, but as soon as a switch is off it's on 5 coin/1 credit. I'll check it with a multimeter here soon and see, have to wait for my co-worker to bring it back in. OH: Edit - Actually I tried to throw it in test mode using the dips, and it wouldn't no matter what. So I'm guessing we should probably replace the dip switches.
You can also go to test mode by pressing the service switch and turning the machine on. The service switch is part of the controls so the buffers for these are on the otherside of the board at 1R and 2R. This should tell you what the dipswitches and controls are doing. If there is corrosion then clean it and find out if any tracks have been eaten away, if so then you might need to make wire bridges across them. However it does sound like the octal buffers are buggered. Testing the dips are working is easy, just measure resistance across them, however measure the pull up resistor packs too as they can cause issues too.
