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twon

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Hi all,

I have a pre jamma version of slap fight that’s giving me some problems. I don’t know what to start looking at first so any suggestions appreciated.
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Are you using an adapter to connect the board up to your JAMMA harness? Does the game play blind? As in, you hear music, sound, and you can insert a coin and start a round? Or is it completely frozen?

Start with disconnecting and reconnecting every ribbon cable connector. Also use a small flat screwdriver to carefully lift each socketed chip out of its socket, spray the socket down with some compressed air, and reinstall the chip. Make sure the notch on the reinstalled chip matches the notch on the socket.
 
The game does play blind and I am using an adapter made by pcb junkie. It has sound but the sound is slower the it should be
 
Alright. Well, try the steps I outlined and let's see if it makes any improvement.
 
So i did everything as you mentioned no change. However when i turned the 5v up on the power supply the sound started to sound correctly. I checked my voltages and fully cranked up i could only get 4.8 v and 11.81 v. I tried it on my other arcade cocktail and was able to crank it up to 5v and almost 13 v and that's when the image completely corrected. I unfortunately cant play it on the cocktail so i don't know why my new astro city psu cant accomplish the same power, Its been recently recapped. Any thoughts on this or ideas please let me know.
 
Good sleuthing by cross-checking the board on another cab. Some old boards can draw a lot of power and 5.0V even should be the target to dial the voltage line to on nearly all boards. The 12.0V line is used to power the audio amplifier and it's more tolerant of undervoltage.

As for what to do about it with your New Astro City PSU - hmmm. Well, you could hack a JAMMA extension to omit the 5V and 12V feeds from the Astro City and have them tie in from an external power supply instead. I'd also verify that your PSU was indeed recapped correctly and that the voltage adjustment pot has the full adjustment range available. If you have a thermal camera, it would be interesting to leave the board running for 10 minutes in your cocktail cabinet and then look at the game board through the thermal camera to see if anything is drawing more power than it should and bleeding it off as excessive heat.

That's all I have off the top of my head - let's see if anyone else chips in with any other ideas.
 
Thanks for all the advice. I don't happen to have a thermal camera but my electrician might. Question about the 5 v pot, did they use to put a safety stop so that you were not able to over jack the 5v, or could it be that the pot could need replacing. I can tell you that my 5v does reach 5v and higher on my jamma edge boards.
 
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This is from the manual saying that -5 volts is required. I know that it’s typically used for sound but i have read that some of the older boards need it to run other things as well. Read up on the new Astro psu and it says it has a very weak -5 output due to a weak transistor and should be upgraded. https://www.arcade-projects.com/threads/question-about-5-voltage-on-astro-city.9143/page-2. Apocalypse in this thread talks about the other things -5v powers. Thinking I might need to swap the transistor. I’ll test it first and see what readings I get.
 
Thanks for all the advice. I don't happen to have a thermal camera but my electrician might. Question about the 5 v pot, did they use to put a safety stop so that you were not able to over jack the 5v, or could it be that the pot could need replacing. I can tell you that my 5v does reach 5v and higher on my jamma edge boards.

There's not really a safety stop on the pot. How it works is that the PSU outputs a maximum voltage and amperage on the 5V and 12V lines at all times. The 5V adjustment potentiometer is a variable resistor on that line. When the pot is adjusted to minimum then the resistance is at the highest, so the lowest amount of voltage makes it from the PSU to the JAMMA harness. When the pot is adjusted to maximum then the resistance is at the lowest (hopefully zero ohms resistance) and the maximum amount of current the PSU can supply makes it to the JAMMA harness.

In your situation, I'd put a multimeter on the solder joints of the 5v adjustment pot (with the power off) and confirm that the measured resistance indeed goes down to zero ohms when the pot is at maximum. A dirty or damaged pot may not function properly and could be applying more resistance to the line than it should.

If the 5V adjustment pot is indeed functioning correctly (zero ohms resistance with the dial at max) then your Slap Fight board frankly draws more power than your Astro PSU is capable of supplying.
 
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I work give it a try and get back to you thanks again
 
So finally got around to checking resistance

counter clockwise which i believe is min i get 0.735 resistance. Clockwise which is max i get 6.7 resistance
 
the .735 reading i get is listed as K ohms the 6.5 reading i get is just ohms no K in front
 
Ended up getting the psu tweeked and got it to push out 5.0v. Thank you importbet. Unfortunately still have a graphic issue. The sound does work perfectly now. It looks exactly the same as the above pictures. I almost feel like its a hold position issue.
 
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