I posted a couple months ago about this OC8820 I found in my father-in-law’s crawl space. I went back and picked it up last weekend and have started to check it out. I started by disconnecting the power supply and checking that voltages looked normal, and they were. So I plugged it in and did and powered it up and not much happened accept for a beep. I stuck a couple floppy’s in the drives, not formatted for this machine just to see if the drives would start up. This time it attempted to read each drive and switched back and forth between the two. So it seems the computer is running and trying to do something. The monitor didn’t show any signs of life though. Adjusting the brightness did nothing, so looks like I have some work to do there.
Then after a few minutes, I heard a sizzle and a nice plume of smoke came out of the power supply. I disassembled the supply, an Astec AA11730, and saw that one of the film capacitors had popped.
So I’m going to have to get the power supply working again and then tackle the monitor. I also need to order on of those floppy emulator devices so I can try loading some software. Hopefully the drives won’t be too much trouble to get working. Here are a few pics.
Here a pic of the power supply showing the bad cap.
This is the main board which includes the floppy drive controller.
And this is the huge video board.
The machine had this tag on the side. Looks like it was used at the Glenview Naval Air Station. Cool!