This was an oscilloscope which had a compressed display that I acquired from a local university . The softkeys (tactile dome switches) under the screen were erratically responsive, so I took them apart and cleaned them. They were working after that. Prior to replacing capacitor C608 to fix the display problem, the display responded to keyboard keys and the softkeys. After the capacitor replacement I was pressing keys - voltage, frequency, print/utility to see what the various screens looked like. The softkeys under the screen were working on the various menus brought up by keys such as voltage, time, etc. IIRC, I pressed the Setup key and the display had a menu of choices at the bottom. I don't remember which softkey choice I made, but I think it was Default Setup, but it could have been Recall. After this the display screen changed to the screenshot below and the scope no longer responded to any keys. I tried shutting the scope off and restarting it. That didn't work. I tried leaving it off longer - over night - that didn't fix it. I assume this is showing something stored in memory, but since I can't get any of the keys to respond, I don't know how to get out of this and get the scope responding again. The first attached photo shows the screen I think I was on before I pressed the softkey that terminated all keyboard responses. The second photo shows the screen it's currently frozen on. I examined the ribbon cables since I had had the front panel off to clean the softkeys and the video board out to replace the capacitor. I didn't see any kinks or loose cables. I reseated the keyboard cable where it attached to the mainboard. The keyboard end was firmly down on its pins. At this point I don't even have a probe to see if it responds to external stimuli. What happened? How do I fix this.
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