Just as the title says. The screen goes black after about 5 to 10 minutes of use. Hitting it on the side with the analog board will bring it back for a few seconds at best but with diminishing returns every time.
The good news is that the computer boots and loads an operating system. SCSI port works. Mouse works, The new floppy drive reads disks and ejects without a problem. All keys on the keyboard work, and I've tested several keyboards on this machine. But the screen still cuts out.
So far, I've recapped the entire motherboard, reflowed all the solder joints (as well as on the motherboard connector for good measure), and replaced the flyback transformer, with no success. Any ideas?