Circus Charlie PCB troubleshooting

ballytablewiz

Well-known member
Joined
Jun 11, 2010
Messages
2,246
Reaction score
140
Location
Arkham, Massachusetts
I have a Circus Charlie PCB that displays garbage. For the first minute or so, it flashes between the screen of garbage I photo'd and a screen full of zeroes. After warming up, the zero screen stops appearing.

From my work with Nintendo stuff, the zero screen is bad cpu, but I don't even know how to identify what kind of CPU/s Konami used on this thing, since they lovingly scraped off any identifying marks and just labeled them "Konami." I also have a badly busted ceramic capacitor right next to what looks like a CPU, which is what I'm thinking causes the zero screen to show during warm-up. (Then again, I've had tons of boards with busted round ceramics that worked fine, so wtf do they even DO anyway?)

Audio is also nonexistent, and coining up changes nothing on-screen. I pulled, verified CRC's with my burner, and reseated every EPROM and they all check out.

Anyone have any ideas for me? And if anyone knows what kinds of CPU/s they used, and this other custom IC (plus where to acquire replacements), that would be swell. See photos 2-5 for chips and relative positions, photo 5 for disc cap, photo 1 for garbage screen.
 

Attachments

  • FILE0484.jpg
    FILE0484.jpg
    89 KB · Views: 32
  • FILE0486.jpg
    FILE0486.jpg
    97.1 KB · Views: 30
  • FILE0489.jpg
    FILE0489.jpg
    94.7 KB · Views: 23
  • FILE0493.jpg
    FILE0493.jpg
    95.5 KB · Views: 20
  • FILE0495.jpg
    FILE0495.jpg
    96.2 KB · Views: 23
There's these magical pieces of paper called "schematics" that people have been nice enough to scan over the years, which correlate between scratched off konami chips and their actual Konami part numbers.

Perhaps you should look into that.
 
The processor is a "Konami-1", which is a custom version of a 6809. But that is not likely your problem. I seriously doubt you'll be able to just swap some socketed chips to get that going. You'll have to break out the schematics and a logic probe and figure out where the data breakdown is.
 
Gee, thanks Rain Man

Well as usual, self-righteous, stuck-up genius boy has provided a practically useless reply. Konami custom part numbers don't do me alot of good without a cross-reference. Which I have Googled for and only found the occasional offhand reference to them, always followed by more useless posts by Mark.

Konami-1 (Matt says it's a "custom" 6809. FPGA says "Custom CPU 42 pin, no replacement available." Yay.)

602 (Not even on FPGA's list)

082 (FPGA lists and crosses, but doesn't identify.)

So if anyone has a cross-reference, and/or some actually helpful info, that would be nifty. As Matt says, socketed IC's are probably not to blame, so any ideas? I do not own, nor have I touched, a logic probe :|
 
Sounds like it's not running code at all, so don't worry about the 602 or the 082 (they're involved in the graphics generation).
Take a look at the LS138 that handles the output enables on the EPROMs.
Check the buffers on the address and data lines (LS244 at 8G and 9H, and the LS245 at 8H).
Check the scratch RAM at 1H and 2H.
 
Adventures In IC Replacement - coming soon to a dingy basement near me!

Sounds like it's not running code at all, so don't worry about the 602 or the 082 (they're involved in the graphics generation).
Take a look at the LS138 that handles the output enables on the EPROMs.
Check the buffers on the address and data lines (LS244 at 8G and 9H, and the LS245 at 8H).
Check the scratch RAM at 1H and 2H.

*BUFFERING* ....

Thanks for the reply. I will attempt to process this information and acquire a logic probe. Specific legs, traces, voltages I am looking for, and how I'd go about that would be killer, since I am a complete layman when it comes to IC repair and replacement.

Everyone is still encouraged to chime in on these processes and other possible solutions and avenues to explore here. Looks like I have another KLOV merit badge to earn.
 
Back
Top Bottom