LyonsArcade
Well-known member
Hi guys;
I've got a Gravitar here i'm trying to ressurect. I rebuilt the monitor tonight with new transistors/caps/etc. from Bob, and it has a pretty nice picture now.
The board is up and running, but the upper right corner of the game is messed up. At first I thought it was just some characters, but on the right and especially the upper right there are just ISSUES. I've taken a bunch of pictures. I checked all the Roms, they're fine. I checked the voltages on the board, they're fine. I swapped the two large Ram chips, and get the same issue no matter what position they're in.
Anybody have any ideas where to look next? I'm trying to decipher the schematics as we speak. Also I'm pretty sure it's a PCB issue, but does anybody know for sure that I've eliminated the WG6100?
When I put it in self test, and get to the screen that's supposed to show ram or rom errors, I DO get the low hum that it mentions in the manual, but the three rom chips it suspects there check out alright. The screen doesn't show any rom errors (that I can read!)
Any help is greatly appreciated! Board is extremely clean, never been worked on.
I've got a Gravitar here i'm trying to ressurect. I rebuilt the monitor tonight with new transistors/caps/etc. from Bob, and it has a pretty nice picture now.
The board is up and running, but the upper right corner of the game is messed up. At first I thought it was just some characters, but on the right and especially the upper right there are just ISSUES. I've taken a bunch of pictures. I checked all the Roms, they're fine. I checked the voltages on the board, they're fine. I swapped the two large Ram chips, and get the same issue no matter what position they're in.
Anybody have any ideas where to look next? I'm trying to decipher the schematics as we speak. Also I'm pretty sure it's a PCB issue, but does anybody know for sure that I've eliminated the WG6100?
When I put it in self test, and get to the screen that's supposed to show ram or rom errors, I DO get the low hum that it mentions in the manual, but the three rom chips it suspects there check out alright. The screen doesn't show any rom errors (that I can read!)
Any help is greatly appreciated! Board is extremely clean, never been worked on.
