link@stew.ssl.berkeley.edu (Richard Link) (10/21/88)
In article <15496@agate.BERKELEY.EDU> link@stew.ssl.berkeley.edu (Richard Link) writes: >The last two days when I powered on my Rainbow in the morning, >the screen flickered up and down quite rapidly, making it impossible >to read anything. Eventually, it stabilized. >I ran the video diagnostics, but there was no report of any problem. >Any ideas? I did not receive any suggestions, and eventually (today) the inevitable occured - the screen flickered incessantly and no longer stabilized. I took apart the system unit and used an air hose to clean the boards and connectors. I also removed the video chip to check for corrosion. I put it back together, and it still did not work. I had one of our electronics engineers look at the screen display, and he said the problem was with the monitor. So we took the monitor cover off, hooked it back up to the system, and turned a few pots. And lo and behold! Here I happily sit typing this message on my Rainbow. The fact that the monitor was at fault explains why the diagnostics reported no video errors (and I should have realized from the diagnostics that it was the monitor) (Whew! I had visions of $$$$$). Anyway, if you're having video problems, poke around inside the monitor (but watch the HV!). Richard Link Space Sciences Laboratory University of California, Berkeley link@ssl.berkeley.edu