arkanoid bootleg missing sound

isucamper

Permanently Banned
Joined
Jan 28, 2010
Messages
429
Reaction score
14
Location
Marion, Iowa
i have an arkanoid bootleg running in an old gorf cabernet that's missing sound. initially i determined that the 12 volts coming from the old linear power supply was dead, which is needed by the c1182 sound amp. i replaced the linear power supply with a switching power supply, and when i try to power the game with a good 12 volts, the game will not boot and the power supply does not generate any of the proper voltages. if i disconnect the 12 volts, the power supply works properly and the game boots (without sound).

i could use some suggestions. should i try replacing the sound amp and / or the capacitors around the sound amp? could the sound amp be causing the board to not boot when it's getting 12 volts?
 
Sounds like a short on the 12V line, which drives the PSU to protect-mode.
1st candidate is the sound amp, then the caps in the sound section.
Desolder the amp and try again.
 
I replaced the sound amp and all the capacitors and resistors in the sound area for good measure. Now the power supply will function and the game will boot when the 12 volts is connected. I can also measure 12 volts getting to the sound amp but I still get no sound from the game. There is a very small pop in the speaker when I apply power and then nothing. The 12 volts coming out of the power supply is actually closer to 13 for some reason, but if I turn down the power supply, then the 5 volts drops down below 5 volts.

I need to do more trouble shooting to find clues, but if anyone has any suggestions let me know.
 
lol sorry. here it is. don't ask me why the numbering on the connector is reversed from the board. this was how i got it. the close in shot is the sound area before i replaced the amp, caps, and resistors.

i have not been able to find a pin-out online anywhere that matches my board. there's a whole bunch of pinouts online, but mine seems a bit different. for instance, the 12 volts was on pin 2 of the solder side, which i can't find a match for anywhere.

I'm starting to suspect that the speaker + and - aren't wired to the right pins on the board because the harness was in a real hacked up state when I got it, but I'm not sure how to go about verifying that.
 

Attachments

  • IMG_5018.JPG
    IMG_5018.JPG
    450 KB · Views: 16
  • IMG_5045.jpg
    IMG_5045.jpg
    217.9 KB · Views: 18
I would use continuity on a DMM to trace the signal from the amp to the edge connector. If there are parts in between, you can still use the same method to trace the output of the amp to the edge connector.
 
The Yamaha YM2149 is the same chip as the AY3-8910. You can check the audio outputs at pins 2, 3, and 38 with an audio probe.
Active PC speakers will work well as an audio probe. ;)
 
I attempted to test the continuity from the amp output to the edge connector, but I don't think I know what I'm doing because I was able to measure continuity at several different pins on the edge connector. Is this because different paths are connected through various capacitors and ground lines? Anyway, I wasn't able to narrow down my speaker output location on the edge connector by doing this.

Thanks for the suggestion on the audio probe thing. I will do some research on it. However, I'm sort of getting close to throwing in the towel on this. I wanted to practice troubleshooting on this board, but it's a bit of a non-started because it's a bootleg and I don't have any information or schematics on it. I might just try to get an authentic Arkanoid board to put in this cabinet, make a new wiring harness for it, and call it good. Then if anything goes wrong with that one I'll have a better shot at fixing it since it will be better documented.
 
The speaker site between the audio-pin of the edge connector and GND. It has only a few Ohms, so mesuring continuity is normal - if you didn't removed the edge connector. ;)

Between the output-pin 5 of the amp and the audio-pin of the edge connector should only be a cap.
 
Back
Top Bottom