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Tech and Marketplace => I need help with my game! - Technical Discussion => Topic started by: lacerta1974 on May 28, 2014, 03:45:49 pm



Title: Tracing Voltages on a pcb
Post by: lacerta1974 on May 28, 2014, 03:45:49 pm
If I have a voltage that I'm tracing coming from the edge connector of a pcb and I come to a capacitor and on the input side of the capacitor I see 5V...then I go to test the voltage on the other leg of the capacitor should I still be getting roughly the same voltage on the other side?


Title: Re: Tracing Voltages on a pcb
Post by: MastarArcade on May 28, 2014, 04:15:46 pm
The short answer is that it depends on the function of the capacitor. It could be a de-coupling cap, which means that its function is to reduce the noise on that particular rail that you're trying to trace. If this is the case, then on one side of the cap, you may see 5V, and on the other side, you'd see 0V because you're probing from GND to GND.

Which game are you trying to work on? If you tell us that, we might be able to dig up a schematic and help you out a bit further.




Title: Re: Tracing Voltages on a pcb
Post by: lacerta1974 on May 28, 2014, 04:54:38 pm
10 pin deluxe bowling...same boards basically as professor pacman.  I have schematics but I really don't entirely understand how to read them just yet.  Still reading up online watching some videos.


Title: Re: Tracing Voltages on a pcb
Post by: MastarArcade on May 29, 2014, 08:58:30 pm
http://www.ballyalley.com/documentation/misc_hardware_docs/Bally/full_size/Bally%20Schematic%20%28Ken%20Lill%29%28August%2024,%202011%29.pdf (http://www.ballyalley.com/documentation/misc_hardware_docs/Bally/full_size/Bally%20Schematic%20%28Ken%20Lill%29%28August%2024,%202011%29.pdf)

So it looks like that 10 pin deluxe uses the Bally Astrocade platform. Which pins are you trying to trace back on the 50 pin Edge connector?


Title: Re: Tracing Voltages on a pcb
Post by: lacerta1974 on May 29, 2014, 10:03:44 pm
We'll I'm just trying to make sure power is getting to where it needs to on the various boards.  I'm getting the proper voltages to the edge of the board.  I've also hooked the monitor up to my centipede machine and confirmed that I'm getting a picture on it.  Honestly I'm new to basically everything.  I figured the next thing I would try is following the power on the pcbs.  I've also replaced all the EPROMs with new burned roms and confirmed the writes on romident. There isn't a lot of info on this particular arcade but I did manage to get ahold of some schematics for it.  Any suggestions would be helpful at this point.  I'd love to get this one working.