Atari System 2 CPU PCB - missing / incorrect sounds

87 t-66

Well-known member
Joined
Jan 31, 2013
Messages
6,575
Reaction score
1,619
Location
North Carolina
Atari System 2 CPU PCB - missing / incorrect sounds

I am troubleshooting an Atari System 2 CPU PCB that is, for the most part, missing audio. I hear a slight ticking sound when the game is on. If I go into the audio self test, I hear audio, but they are the incorrect sounds. Sometimes the audio self test will produce a constant single tone. I have verified the issue is not any of the socketed chips on the board. Voltages are good. Any ideas would be appreciated. Here is a link to the schematics: http://arcarc.xmission.com/PDF_Arcade_Atari_Kee/Paperboy/Paperboy_SP-275_1st_Printing.pdf
 
What testing tools do you have? Audio is going to easier to diagnose with an Oscope?

Because you don't specifically mention it: When you power up with the self test switch on do all the RAM/ROM tests pass? These tests don't run when you throw the test switch after the game boots. I can run my CS with a bad CPU ROM (socket is bad and I haven't fixed that yet).

Beyond that, you mention that you tested the socketed chips. I'm making an assumption that you tested them off board. You should inspect the sockets. I'm plowing through a bunch of system 2 stuff and find that the sockets are commonly bad on 1 or 2 pins and the game will run like that.
 
I have a scope and logic probe. I took all of the socketed chips out and put them into a second board I have and they work fine. I'm working on building a test harness so I don't have to keep pulling my cabinet out. Will need to wait and try booting into the self test till I get my wiring done. Hopefully tomorrow
 
Cool, the scope is going to help the most here. Post up the results of the power up self tests when you get it all wired up.
 
I was missing one of my audio channels in my champ. Sprint. Replaced a tda2002 at q9 and im back in business.
 
Back
Top Bottom