I've been wrestling with some sound issues on my ICB. This may get a little wordy as I describe my issue and detail what I've done so far....
The game was working, then one day I turn it on and….certain sounds are faint in the speaker while others sounds normal.
Sounds that work fine:
-Heartbeat countdown
-Left motor move up/down
-Right motor move up/down
-Initial "pssht" and gurgling sound when the game is first powered up. (I guess this simulates cracking open and pouring a beer).
Sounds that are faint in the speaker:
-Target Hole
-Non-Target Hole (the oops sound)
-Bonus score counter
-Credit ("pssht" sound...the cracking open a beer sound)
-Tilt
-Music (99 bottles theme, and game over tune)
Adjusting the volume pot makes the working sounds louder, but the other sounds are still faint in the speaker.
Here is what I've done so far...
The volume pot seems to be working fine since I'm able to adjust the volume of the sounds that are working. There is also a rise and fall of static in the speaker as I turn the pot louder and softer.
I replaced the amp at U38 on the pcb.
I replaced the sound mixer at U33 on the pcb.
It seemed like I had working 8910 chips at U9 and U10 on the pcb.
According to the manual U9 should be driving some of the sounds that are faint, so I thought I'd try replacing that IC.
I got an 8910 from Bob, but when I tried to use it, it made things worse. The game wouldn't start properly and didn't function. U9 is responsible for some other function like interfacing with the watch dog timer, according to the manual. So, I put back the original chip and the game functions fine...but with the same sound problem.
And, just to be sure, I tried a different speaker, still the same issue.
I'm not sure where to go from here other than keep replacing components on the board. There is a MC68A21 chip at U28 on the pcb that seems to work with the IC's at U9 and U10. I thought I might try replacing that.
Any thoughts/advice/suggestions would be appreciated! This is one of those little annoying issues that is driving me nuts and a fresh perspective might help.
Thanks
The game was working, then one day I turn it on and….certain sounds are faint in the speaker while others sounds normal.
Sounds that work fine:
-Heartbeat countdown
-Left motor move up/down
-Right motor move up/down
-Initial "pssht" and gurgling sound when the game is first powered up. (I guess this simulates cracking open and pouring a beer).
Sounds that are faint in the speaker:
-Target Hole
-Non-Target Hole (the oops sound)
-Bonus score counter
-Credit ("pssht" sound...the cracking open a beer sound)
-Tilt
-Music (99 bottles theme, and game over tune)
Adjusting the volume pot makes the working sounds louder, but the other sounds are still faint in the speaker.
Here is what I've done so far...
The volume pot seems to be working fine since I'm able to adjust the volume of the sounds that are working. There is also a rise and fall of static in the speaker as I turn the pot louder and softer.
I replaced the amp at U38 on the pcb.
I replaced the sound mixer at U33 on the pcb.
It seemed like I had working 8910 chips at U9 and U10 on the pcb.
According to the manual U9 should be driving some of the sounds that are faint, so I thought I'd try replacing that IC.
I got an 8910 from Bob, but when I tried to use it, it made things worse. The game wouldn't start properly and didn't function. U9 is responsible for some other function like interfacing with the watch dog timer, according to the manual. So, I put back the original chip and the game functions fine...but with the same sound problem.
And, just to be sure, I tried a different speaker, still the same issue.
I'm not sure where to go from here other than keep replacing components on the board. There is a MC68A21 chip at U28 on the pcb that seems to work with the IC's at U9 and U10. I thought I might try replacing that.
Any thoughts/advice/suggestions would be appreciated! This is one of those little annoying issues that is driving me nuts and a fresh perspective might help.
Thanks
