>> Heh, well I got an 8-year-old AppleColor High Resolution RGB 14" monitor 
>> on my IIsi and the same on my IIfx and the one on the IIsi went pink and 
>> the one on the IIfx went yellow.. the IIsi one finally died completely 
>> after a year of pink, and the IIfx one still works.. I find lightly 
>> tapping the monitor in the back to have worked :) It would go back normal 
>> sometimes for less than a minute, sometimes for days, and then it'd jump 
>> back to bening yellowish. :) Now those monitors are old (we FINALLY 
>> bought a G3 with a 17" AppleVision so now I have a modern-day computer! 
>> Although those old Mac IIs were rough&tough machines, very well built, 
>> beautioful feel, plus NetBSD works on the IIsi, not on the G3 :))
>
>I ran into problems w/ my 14" monitor. It turned out to be a solder
>problem. On the PCB which connects to the tube, the solder joints for the
>connector had eroded. A little touch-up w/ a soldering iron, and it worked
>great. If a slap on the side works, sounds like it's a connection problem.
>So you might look for weak solder links (*).
>
>(*) remember that video monitors generate HIGH voltages, and often involve
>capacitors which can store these voltages for a while. Be sure to either
>work with the thing unplugged, or be VERY careful. You're at your own
>risk.

I've run into this too, another problem may be the cable, if it it pushed
back against a wall and the cable has pressure on it it can cause shorts
and break cables inside the insulation, etc.  That is a rather annoying one
and can sometimes require getting a replacement cable... sometimes
depending on the monitor you may have to solder a new one internally which
really sucks.  Again, like Bill said, be VERY careful.  Not only does it
have a nasty charge when plugged in, it can keep one when unplugged if the
discharge coils (if it has any) go bad.  It can have enough power to throw
you a few feet, kinda painful...

		Good luck,
			Kevin