Joust problems.

gooze

Member
Joined
Oct 19, 2008
Messages
121
Reaction score
0
Location
Fountain Hill, Pennsylvania
Hey Guys, once again I could really use some help. I turn my Joust on and at first it get a ram error, but still booted and played ok. After turning it off and turning it on everything is doubled. I attached a pic so you could see what I mean. Any help would be greatly appreciated!
 

Attachments

  • IMAG0268.jpg
    IMAG0268.jpg
    79.8 KB · Views: 25
  • IMAG0269.jpg
    IMAG0269.jpg
    84 KB · Views: 24
yeah uh.. I think a ram problem may very well cause this.

how are your voltages looking, and have you tried reseating the rams?

that's my best guess. I don't know how commonly the rams fail on these but considering they're almost 30 years old I'm sure they do now.
 
I have one that did that. It turned out to be the video addressing chips, not the RAM chips. If it was the data addressing chips, it would not pass the power up RAM test.

Internally, the RAM is dual ported. There is a CPU bus and there is a video bus. If it passes the RAM test and the video is hosed, it is a video bus issue. If it doesn't pass the RAM test, it is a CPU bus issue.

ken
 
Internally, the RAM is dual ported. There is a CPU bus and there is a video bus. If it passes the RAM test and the video is hosed, it is a video bus issue. If it doesn't pass the RAM test, it is a CPU bus issue.


Uh, not it's not... There's separate data in and data out pins, but that's far different from being dual ported....

It's probably just a video decoder prom issue, or perhaps a bad 74153.
 
I took out the board that had the ram on it. Pull all the chips, cleaned them and the board with some electronic spray cleaner, put it back together and all systems a go! Thanks for the help guys! I really appreciate it.

I was surprised on how easily some of the chips came out. I think from now on when after moving a game I'm going double check all the chips to make sure they're tightly in there.
 
Back
Top Bottom